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| Established in 1952 | |
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Probe Characterizing Spheres ( aka probe calibration spheres, probe character sphere
or datum spheres ) are used to evaluate and determine
compensation needed for errors in C.M.M. measuring
probes. Most errors and problems on C.M.M.'s are in the
probe. This should be the first measuring device
purchased to check the C.M.M. See: Technical Data Sheet: CMM-7. |
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PM-PB-B75 / PM-UB-B75 |
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 PM-PB-B75R / PM-UP-B75-R The Runt Probe Sphere |
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 PM-PB-B100 / PM-UB-B100 Standard Probe Sphere |
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 PM-PB-B100R / PM-UP-B100-R The Runt Probe Sphere |
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 PM-B0-200 The Big One |
The first consideration is to determine what diameter should the master calibration sphere be?
On most modern C.M.M.'s the probe fitting software will accept almost any diameter spherical master. The most common master spheres have been one inch, ( 1.00", 25.4 mm ), and three quarters of an inch, ( 3/4", 0.75", 19.05 mm ); but 28 mm (1.102 inches) and 30 mm (1.181 inches) diameter have become more popular as C.M.M. technology has taken on a more European focus.
The more popular sizes of master calibration spheres are less expensive. Changing the master calibration sphere diameter will not compromise the C.M.M.'s performance in any way.
When using very small diameter spherical contacts on the measuring probe, choose much smaller diameter master calibration spheres to accurately characterize these small diameter contacts. The three most popular diameters for the master calibration spheres for smaller diameter probes are 4mm ( 0.157 inch ), 6mm (0.236 inch ) and 10 mm ( 0.3937 inch ). The smaller diameter master spheres are used to calibrate the smallest probe spheres and so on with the larger diameters. The problem of serious wear of the small diameter master spheres, due to the high contact force, makes it almost mandatory that these small diameter spheres be made of Tungsten Carbide. This is a necessary compromise because there will be some built in error due to the high stiffness of the T.C. material.
The choice of material for the master calibration sphere can be of great importance, depending on the contact force of the measuring probe and its spherical diameter. The important factor in the choice of the material for the master calibration sphere is its stiffness. When the probe contacts the master calibration sphere, there is considerable Hertzine elastic deformation of both the master calibration sphere and the spherical contacts of the probe. The amount of these deformations depends mainly on the probe sphere diameter and the contact force of the measuring probe. The smaller the probe ball, and the higher the measuring force, the more elastic deformation will occur. If we use a very stiff material like ceramic or tungsten carbide for the master calibration sphere, and then measure ordinary materials such as aluminum or steel; we will loose appreciable accuracy. This built in error will be greater with the high measuring force typical of many of the modern scanning probes and will be higher for small diameter probe spheres than for the larger ones. The nearer the stiffness of the master calibration sphere matches the stiffness of the part being measured, the less error will result. For this reason, steel calibration spheres have been the order of the day until recently.
If the master calibration spheres are replaced in kind, all standard diameters of ceramic and tungsten carbide master calibration spheres are available.
The next variable is choosing the design for the post used to hold the master calibration sphere. The one important word here is the rigidity of the post. What is needed, is a robust stiff structure that will still allow full access of the master calibration sphere by the measuring probe.
When simple vertical or horizontal probes are being calibrated, the standard very rugged "PB" series calibration spheres on a very stiff post are most accurate and by far the least expensive choice. See our web page number 2270 for more information.
When calibrating more complex articulating probes and compound star probes, more complete access to the master probe calibration sphere is required. The first and least expensive of the complex probe calibration devices is the "Slim Probe" Calibration system. It consists of one or more master calibration spheres mounted on very slender, extremely high stiffness cermet rods. These one eighth of an inch 0.125" (3.2mm) diameter, extremely rigid cermets rods allow almost complete access to the periphery of the master calibration sphere or spheres.
This more complex design and more expensive components cost about a 20% premium, over the standard PB series probe calibration spheres.
When the fastest most accurate calibration, of complex star and tree probes, is required the device to specify is the "Star Probe Calibration Device". This arrangement uses five exactly matched master calibration spheres. One sphere is positioned vertically, and the other four are arranged horizontally at ninety-degree increments (see details of this device in the technical data sheet under C.M.M. products). The very rigid three quarter inch, 0.75" (19mm), mounting posts that hold the five master calibration spheres are securely fastened to a robust two inch, 2" (50.8 mm), diameter pole, that is in turn fastened to a four inch, 4" (101.6 mm), diameter ultra stable platform.
The significance of this design is that the area of one master calibration sphere that is covered up by a support post is exactly opposite another matching calibration sphere, where that area is completely exposed. Subtract the fixed distance between the two spheres to get a 100% calibration of even the most complex probes.
Calibrating measuring probes with very small diameter contact tips requires small diameter master calibration spheres mounted on small diameter posts.
These parameters become even more critical when small diameter complex probes are used in the scanning mode. For these applications, a petite version of the star probe calibration device is available (see details under C.M.M. products).
Optical probes form a very broad spectrum of devices, but they respond well to rather limited range of master calibration devices.
The one "no no" for optical calibration devices is bright shiny artifacts.
The least expensive calibration sphere is the satin finished stainless steel ball. Some optical probes respond very well to satin finished titanium, which has a very flat gray surface. The most popular master calibration sphere for optical probes is satin finished aluminum oxide ceramic, which is very white but very dull. All of the metal balls suffer from the tendency to get burnished stripes on the surface that affect the calibration. This burnishing is caused by almost any physical contact with hard materials. This does not happen to the aluminum oxide ceramic. The very white surface of the ceramic ball gets dirty very quickly, but it can be easily cleaned with coarse hand soap.
Very short Ball Bars (Dumbbells), with satin finished ceramic balls are a very popular calibration device. The post next to the balls is black oxide coated so they don't effect the calibration.
To facilitate the holding of these very short Ball Bar
(Dumbbell)s, we have developed the "Hammer." (See the technical data
sheet under C.M.M. products). The Hammer has a right-angled post
that is used to hold the Ball Bar (Dumbbell) in our standard
clamping hardware.
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This Probe Characterizing technique uses computer software and an extremely high quality spherical artifact of a well known diameter to calibrate the radius of the contact tip. It will characterize geometry errors of the measuring probe (probe lobbing), it will compensate for bending of the probe stem and a broad range of other elastic deflections or bending moments throughout the machine. The sphere is very rigidly fixed to the C.M.M. table for this test. In effect, the C.M.M.'s computer is told that it is measuring a perfect sphere of a specific diameter and that any departure from this ideal form should be corrected in all future measurements. Some C.M.M. software is written around a specific master sphere diameter while other software is open to selection by the user. |
The most widely used sphere diameter is one inch (25.4mm) but 3/4 inch (19.05mm) is also widely used. In our experience down to about 10mm (.3937 inch) diameter, the smaller the master sphere used, the more accurately probe lobbing will be compensated for. This correction ends up being a simple adjustment in the apparent radius of the contact tip of the measuring probe.
2.1 This same spherical artifact makes an excellent Coordinate Measuring Machine repeatability test device. Its position on the table and its diameter are simply measured a considerable number of times (usually ten to twelve), and the results are compared. Each measurement consists of a small number of well distributed hits. Any variations in the measurements reflect a lack of machine repeatability. Valuable information about specific machine performance can be learned by looking at the end positions of individual axii. Note that this test must be performed as quickly as possible to avoid the influence of temperature drift.
Part Number: BLK-45 |
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45 Degree Angle Block is used to
hold Probe Characterizing Spheres inclined at 45 degrees,
so they are more accessible for C.M.M. calibration. |
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| Part # | Description | Price | Purchase |
| BLK-45 | BLOCK, 45 DEGREE | $98.13 |  |
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The Abalone (Part #10140) was originally developed as a clamping device for holding the Anchor and Ball Bar (Dumbbell) combinations on the tables of Coordinate Measuring Machines. Since then, it has found wide use for a variety of clamping and work holding tasks on C.M.M.s surface plates and machine tools. The Abalone is a powerful vacuum hold down device. When used with a good vacuum pump, the five inch diameter (127mm) base will provide over 290 pounds (131kg) of clamping force. The one and one quarter inch (31.75mm) thick aluminum device weighs only two pounds (.9 kilograms). It is hard coated and the base is precision lapped flat for good mechanical stability, long wear and to form a good vacuum seal that will assure the highest clamping force. |
A M10x1.5 threaded hole is provided in the top center of the Abalone to attach the Anchor. For added utility, there are four M10x1.5 drilled and threaded holes around the outer edge of the upper surface. These threaded holes facilitate the rigid mounting of other tooling.
| Part # | Description | Price | Purchase |
| 10140 | ABALONE, 5" DIAMETER X 1.5" THICK | $150.00 | |
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When three of these devices (Part #40320) are rigidly attached to diagonal corners of a Coordinate Measuring Machine pallet, it will exactly define the pallet's three dimensional address or position on the measuring machine table.
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The relative position of these threaded tooling balls defines the fixed location points that are used to exactly position the test part on the pallet system. This approach to locating the pallet is a tremendous time saver.
These devices actually allow a pallet to be randomly positioned anywhere on the C.M.M. table, and yet the computer has a perfect knowledge of the test part's true three dimensional position. This location is retrieved from the data that was stored during the original measurement of the test part some time earlier.
The three exactly matched hardened stainless steel balls are three quarter inch (1.9 cm) diameter. They are precision lapped spherical within less than five microinches and the surface is polished to a fraction of a microinch.
The sphere is securely attached to the head of a short 1/4 inch (6.3 cm) diameter stainless steel bolt that has twenty threads per inch.
To prevent a slight bump from separating the ball from the bolt, a 1/8 inch (3.2 mm) diameter pin extends well up into the ball and down into the bolt.
A stainless steel washer and a jam nut are supplied with each threaded address sphere to rigidly fix their position on the pallet.
In addition to their use for locating the position of a pallet on the C.M.M. table, these devices make an excellent measuring artifact and two or more of them left mounted on a pallet can form an interim checking device.
A large array of these balls can be mounted on a simple piece of metal plate to construct a very high quality ball plate for Coordinate Measuring Machine Evaluation.
When building a large artifact using many balls, the balls should be ordered as a single master set so that all spheres will be exactly the same diameter.
| Part # | Description | Price | Purchase |
| 40320 | ADDRESS SPHERES, SET OF THREE | $96.77 | |
| 40320 | CHROME STEEL BALL 0.345233", 8.768918 mm Grd:25 | $7.50 | |
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For reliable evaluation of the Portable Arm Coordinate Measuring Machines, rather large calibration artifacts are required. Although a number of different length artifacts have been supplied, the industry is trying to standardize on 2.3 meters ( 90.55"). These large calibration devices must remain dimensionally stable during the evaluation sequence. This dimensional stability must be physical stability. By this, we mean that the ball bar must not distort mechanically when the test probe actually makes physical contact with the calibration object. |
This mechanical stiffness must be maintained on these rather large devices, but at the same time they must still be light weight enough for portability in the field and so that a single technician can manipulate them through the 20 to 35 positions required to meet the ANSI B89.4. 1-1997 specification for the "Performance Evaluation of Coordinate Measuring Machines".
This rather daunting problem is further complicated by the fact that large objects are very sensitive to small variations in temperature. An eight foot (96-inch) [two point four meter] long aluminum bar will expand more than one thousandths of an inch (.025mm) for each degree F. of temperature rise. For steel it is over one half of a thousandths of an inch (.013mm) per degree F.
The same eight-foot (two-point four-meter) structure made of Invar® will only expand sixty-five microinches (1.7 micro meters) per degree F.
The realization of lightweight, good rigidity, and low temperature sensitivity are all achieved by building a composite structure of a series of round tubular Invar™ members, clamped together by a number of robust bulkheads. The tubular structure provides the stiffness and the light weight, while the ultra low expansion properties of Invar¨ solves the temperature sensitivity problem.
This large device must be supported on a metrology platform with the same rigidity, light weight, and low temperature sensitivity as the artifact itself, so we have devised a Metrology Tripod with the very same design features as the Portable Arm C.M.M. Calibrator, see our Technical Data Sheet CMM-24. The large tubular Invar¨ structure is supported on the tripod by a ball bearing turret that allows it to be easily positioned at any angle from vertical to horizontal.
There is another unique problem in evaluating the performance of a portable arm C.M.M., when using a hard probe it is difficult to make a single only contact with a small calibration artifact. This is even more difficult when probing a sphere, which is the standard A.N.S.I. artifact. The machine has difficulty identifying one only point on an infinitely varying target. A unique way to cope with this problem, while still using a spherical target has been developed. A very precision sphere of rather large diameter between 0.59-1.00 inch ( 15 mm to 25 mm ) is used as the measuring probe. A Three Ball Kinematic Coupling is rigidity mounted on the face of each of the four bulkheads that hold the Invar™ tubing together, and a fifth is mounted on the top center of the turret. By placing the large probe sphere in the Three Ball Kinematic Coupling a single only point in three-dimensional space is described. In order to make the hit more positive, the Three Ball Kinematic Coupling has a light magnetic preloading.
The Kinematic Coupling is made up of three high grade, five sixteenths of an inch ( 5/16", 0.3125", 7.9 mm ) diameter tungsten carbide balls. Each of these balls have a deep hole drilled in them. At assembly, they are glued over a high shear strength pin into individual spherical cavities in the face of the bulkheads. This design provides maximum strength with great shear resistance and a very thin glue line that prevents hygroscopy due to moisture absorption.
The 1216 Ball Plate is a simple, inexpensive and very
versatile device for Coordinate Measuring Machine calibration and
evaluation. The Ball Plate consists of a rather large rigid 12
inches (305 millimeters) by 16 inches (406 millimeters) plate
that is 1.5 inch (38 millimeters) thick.
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Standard 1216 Ball Plate with Grade 5,
Polished, Stainless Steel Balls |
Satin Finished Ceramic Balls on a
Flat
Black Plate for Optical Evaluation |
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There are a series of 20 ultra precise 19 millimeter (.748 inch) diameter, hardened stainless steel or aluminum oxide ceramic balls permanently mounted on the top face of the plate. To reduce the weight for ease of handling, the rear surface of the plate is relieved so that the complete plate weighs only 19 pounds (8.6 kg).
The very nature of a spherical geometry is unique in that it is the only form that has a single point that describes its exact position in three-dimensional space. The perfection of this point is only limited by the sphericity and surface quality of the ball. In addition to their having exceptional sphericity, the entire 20 ball set is carefully selected to be as exactly the same diameter as possible.
These ultra precise balls are spherical within less than 0.000005 inches (127 nanometers) and all 20 of the balls in the set are matched for size within 0.000005 inches (127 nanometers). These micro grain stainless steel balls are hardened to 58 HRC minimum and thermo cycled to develop long term dimensional stability.
The aluminum plate can be black anodized and equipped with satin finished ceramic balls for optical applications. It is also available with ceramic balls.
The real value of the Ball Plate over other artifacts is its ability to make a fast accurate every day or interim evaluation of the measuring machine's performance. The term value is used here, as a ratio of is performance to its cost. This cost is both its initial cost and the cost to use it in everyday operation. The large number of almost perfect sphere center to sphere center addresses tests all aspects of the C.M.M. system's performance, and it does it very quickly. Each of the 20 balls has an engraved number on the plate to identify it.
How can you avoid the very expensive laboratory calibration that is typically expected to be made on all calibration devices? What an interim or everyday evaluation is trying to achieve, is to make sure that all aspects of the machine are performing properly in between yearly calibrations. Immediately after the technician completes the annual machine calibration, place the Ball Plate on your machine and measure it. To be extra careful, rotate the Ball Plate 90 degrees and measure it again. For all practical purposes the spherical artifacts on the Ball Plate are themselves perfect. What you are doing by measuring their position on the Ball Plate is calibrating the Ball Plate within your machine's resolution. On this first measurement, the machine is calibrating the Ball Plate, and at the same time the Ball Plate is checking the machine.
When you are audited, you can point to your Ball Plate as the device used to evaluate the everyday or interim performance of this machine. Even when the question of traceability comes up, you have an unbroken documentation chain going back to the laboratory artifacts used by the technician for the machine's yearly calibration.
The Ball Plate is an excellent device for doing a complete yearly C.M.M. calibration; but when used in this mode, the Ball Plate itself requires a periodic laboratory calibration that is very expensive. At the very minimum, the exact three dimensional distance from the number one (#1.) master ball to each of the other balls on the plate must be mapped.
Doing the complete calibration of a C.M.M. by measuring the Ball Plate in the number of different positions required is quite time consuming, but extremely accurate. A rather elaborate on board software package is required to analyze this measurement data and to pinpoint the error sources, so that they can be manually corrected or software compensated.
See also: Three Dimension Ball Plate, 12" ( 30.48 cm ) X 16" ( 40.64 cm ).
| Part # | Description | Price | Purchase |
| 1216 BALL PLATE | BALL PLATE, 12 X 16, PRECISE STEEL BALLS | $1800.00 | |
| 1216-SAT | BALL PLATE, 12 X 16, SATIN FINISHED BALLS | $1800.00 | |
| 3DBP12X16 | THREE DIMENSION BALL PLATE, 12" ( 30 CM ) X 16" ( 41 CM ) | $2500.00 | |
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The three-dimensional, 3D, ball plate is one of the oldest calibration devices for the evaluation of Coordinate Measuring Machines. It dates back to the beginning of the commercial use of C.M.M.'s, where it was used with hard probes (conical cups) to evaluate the machines' overall performance. There are three mating pairs of precision ground and lapped cylinders that are rigidly mounted in three precision-machined trenches in the bottom surface of the upper platform. These three pairs of cylinders form three Kinematic Vee Blocks. This upper platform containing the nine spherical masters can be removed and replaced any number of times, within less than one microradian. Building a practical three dimensional ( 3-D, 3D ) calibration artifact for modern Coordinate Measuring Machines is a tricky proposition. To be of any practical value, the artifact must be fairly large. It also must be rugged enough to be mechanically stable. This means that it must be able to withstand at least moderate handling and shipping abuse, but still be able to perform its task. It must remain dimensionally stable over long periods of time. The materials used must not twist or turn. They must not grow or shrink with time. This job is accomplished by erecting a series of nine very rigid vertical posts, of different heights, from the surface of a stiff, flat pallet. The standard post heights are 12 inches (305 mm), 6 inches (152 mm) and 2 inches (51 mm). |
 Base for Three Dimensional Ball Plate |
On the top of each of the nine vertical posts is rigidly attached a very precise master sphere.
For use on machines with touch trigger, or other mechanical probes, a one-inch (25.4 mm) diameter sphere is normally used. These spheres are made of a very high chrome, high carbon, Martensitic stainless steel. This ultra fine grain material is hardened and thermal cycled to produce a minimum hardness of 58 HRC (Hardness on the Rockwell "C" scale). This special thermal cycle promotes long term dimensional stability.
All nine of the balls are precision lapped spherical and exactly same the diameter within five micro-inches (one hundred twenty five nanometers) tolerance.
When the C.M.M. probe used is a non-contact laser scanner of other optical device, the balls used are usually a satin finished white ceramic material. The reduced surface quality of these satin finished balls limits the sphericity and common diameter to twenty-five micro-inches (0.63 micrometers). Balls made of many other materials, and diameters, can be supplied on special order. Satin finished steel and titanium are two of the more common.
The rather large dimensions of the 3 D Ball plate, that are 12 inches (305 mm) by 16 inches (406 mm), requires an exceptional mounting method to avoid mechanical distortion. This is made more important, as any bending of the plate will cause serious first order errors in the spacing of the balls on the tops of the rather long posts.
In order to gain perfect repeatability of all the elastic deflections, the platform of the 3 D Ball plate is Kinematically mounted.
The base for this kinematic mount consists of a triangular aluminum casting that is rigidly attached to the CMM table. Three high quality, hard Martensitic stainless steel, spheres, are rigidly mounted at the corners of this triangle.
The Kinematicaly mounted upper platform is equipped with two sets of isolated handles to facilitate placing it in position on the triangular platform, without any personal contact with the metrology elements.
Even though the 3-D Ball Plate is rather large and very rugged, it weighs only 30.5 pounds (13.84 kilograms). This is well below the 44-pound O.S.H.A. limit, to be handled by a single technician.
The device can be custom built in other dimensional configurations. It can be configured with taller or shorter posts. It can also be built on a larger or smaller pallet. It can have a totally different aspect ratio, so that it is long and narrow.
| Part # | Description | Price | Purchase |
| 1216 BALL PLATE | BALL PLATE, 12 X 16, PRECISE STEEL BALLS | $1800.00 | |
| 1216-SAT | BALL PLATE, 12 X 16, SATIN FINISHED BALLS | $1800.00 | |
| 3DBP12X16 | THREE DIMENSION BALL PLATE, 12" ( 30 CM ) X 16" ( 41 CM ) | $2500.00 | |
 The Big One, CNC evaluator, show with shipping case |
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| Solidworks rendering of The Big One |
The "Big One" (Part Number BO-PM-B200) is a giant 2.00 inch (50.8mm) diameter precision sphere mounted on a rugged 2.00 inch (50.8mm) diameter by 2-1/2 inch (63.5mm) high steel post.
It was developed for the evaluation of Computer Numerically Controlled Machining Centers according to ANSI/ASME B 5.54.1992. It is also used as a probe characterizing sphere on some Coordinate Measuring Machines. The large target is particularly well-suited for use on big machines and on multi-spindle machines.
Some of these tests include Machine Tool Repeatability, Temperature Variation Error, Hysteresis, Feature Accuracy, Pallet Change Repeatability, Tool Changer Repeatability, Drift, Vibration and Compliance.
The surface area of this 2.00 inch ( 50.8mm ) diameter sphere is 12.566 square inches ( 319.19 square mm ) which is four times the 3.1416 square inch (79.797 square mm) area of the standard 1.00 inch ( 25.4 mm ) diameter sphere commonly used.
The 2.00 inch (50.8mm) diameter precision sphere is made of very fine grain high chrome, high carbon stainless steel that is hardened to 58 Rc for wear resistance and cold cycled for long-term dimensional stability. This large diameter component is lapped spherical within 5 millionths of an inch (127nm) and has a surface finish below 0.7 micro inches (17.78 nm) Ra. The exact diameter of the sphere can be certified to 10 millionths of an inch (254nm).
This design uses a unique high strength connection to join the precision sphere to the post. An Electrical Discharge Machine ( EDM ) is used to drill a concentric hole deep into the already finished sphere. This space age process uses millions of tiny bursts of electrical energy to erode a hole into the precision sphere without affecting the original quality. The end of the post has a corresponding hole drilled in it. As the high strength glue is applied to the assembly, a steel pin is inserted between these holes to form a very strong connection.
The flat base of the mounting post is recessed to leave an anular ring forming a stable connection for the sphere.
The post of the "Big One" is provided with an attractive black oxide finish that resists corrosion. A 1/4 inch (6.35mm) diameter clearance hole is cross-drilled through the post and a high tensile stainless steel pin is provided to tighten and to remove the device from its mount.
A M10 x 1.5 tapped hole is machined in the center of the flat base of the post to provide a strong means of attachment. This configuration is standard throughout the product line so that all components are interchangeable.
| Part # | Description | Price | Purchase |
| BO-PM-B200 | BIG ONE, THE, 50.8 MM, 2 INCHES, 2.5 INCH POST | $391.75 | |
| BO-PM-SAT-B200 | BIG ONE, THE, SATIN FINISHED 50.8 MM, 2 INCHES, 2.5 INCH POST | $391.75 | |
| BO-EP-3 | BIG ONE, EXTENSION 3 INCHES, 2" DIAMETER | $35.85 | |
| BO-EP-6 | BIG ONE, EXTENSION 6 INCHES, 2" DIAMETER | $35.98 | |
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Assembling the individual kinematic components into a completed coupling is usually done by securing them in position with a high strength epoxy glue. These high strength industrial quality glues are usually packaged in very large volumes that are not at all practical for small projects. For mixing industrial glues the proportions of catalyst to polymer is quite small so the mixtures are critical and must be carefully weighed out. |
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We convinced the manufacturer of our favorite extreme strength epoxy glue to package it in small tubes for our customer's convenience. To make it more practical, the constituents are formulated so that two stripes of equal volume are laid down and thoroughly mixed to produce a glue. This will cure in one day, at room temperature, to have the exceptional sheer strength of 3000 pounds per square inch, or 21kg per square centimeter. The Epoxy glue can be ordered as Part #: EG3000.
When mixing the epoxy, squeeze out the two strips of at least one and one half inches (38mm) long, even if you only need a small amount! This is important because a small error in small amounts of the constituents will have a dire effect on the resulting properties of the glue. On the other hand, a small error in much larger amounts of the two constituents will have little effect. You may remember from your school chemistry class, this concept is called barrel chemistry.
Epoxy glue is not compatible with water even when it is fully cured. Keep the layer of glue between the kinematic component and the platform as thin and uniform as possible. Use isopropyl alcohol to remove any surplus glue from around the kinematic components while the glue is still liquid. This will limit the exposure of the glue line to the atmosphere, reducing moisture absorption.
| Part # | Description | Price | Purchase |
| EG-3000 | EPOXY GLUE TUBE | $14.10 | |
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Standard Extensions raise and
extend C. M. M. Probe Characterizing and C. N. C.
Target Spheres. They are also used to securely couple
measuring devices to the C. M. M. or C. N. C.
table. |
Two standard lengths of this version are available. The 3.00 inch (76.2mm) long version (Part Number P-EP-3) and the 6.00 inch (152.4mm) long (Part Number P-EP-6).
The 1-1/4 inch ( 31.75 mm ) diameter extension posts have a 3/16 inch ( 4.76 mm ) clearance hole cross-drilled through the post diameter. A high tensile stainless steel pin that passes through this hole is used to tighten and to remove the device from its mating part.
Extensions for "The Big One" ( Part Number BO-PM B200 ) are 2.00 inches ( 50.8 mm ) diameter to match its post. Two standard lengths of this version are available. The 3.00 inch ( 76.2 mm ) long version ( Part Number BO-EP-3 ) and the 6.00 inch (152.4 mm ) long (Part Number BO-EP-6).
The 2.00 inch ( 50.8 mm ) diameter extension posts have a 1/4 inch ( 6.3 mm ) diameter clearance hole cross-drilled through the diameter of the post. A high tensile stainless steel pin that passes through this hole is used to tighten and to remove the device from its mating part.
Both ends of all extension posts are drilled and tapped M 10 x 1.5. This configuration is compatible with our full line of accessories.
The center portions of both of the flat ends of all extension posts are recessed to leave annular ring. This flat ring forms a stable connection with the mating parts.
All extensions are provided with an attractive black oxide finish which resists corrosion.
| Part # | Description | Price | Purchase |
| BO-EP-3 | BIG ONE, EXTENSION 3 INCHES, 2" DIAMETER | $35.85 | |
| BO-EP-6 | BIG ONE, EXTENSION 6 INCHES, 2" DIAMETER | $35.98 | |
| P-EP-3 | EXTENSION, 3 INCHES, 1 1/4" DIAMETER | $34.68 | |
| P-EP-6 | EXTENSION, 6 INCHES, 1 1/4" DIAMETER | $35.85 | |
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The 4.00 inch (101.6 mm) diameter magnetic platform was developed to hold the target sphere for evaluating Computer Numerically Controlled Machining Centers according to ANSI-ASME B 5.54-1992. The commonly used target sphere is a 1.00 inch (25.4 mm) diameter Ultra Precise Sphere mounted on a 1-1/4 inch (31.75 mm) diameter post, (Part Number PM-UB-B100, see Technical Data Sheet CMM-7). |
Another popular target sphere that is compatible with this magnetic platform is the "Big One". It is particularly well-suited for the evaluation of large and multi-spindle machines. This device (Part Number PM-PB-B 200, see Technical Data Sheet CNC-1) incorporates a huge 2.00 inch (50.8 mm) diameter sphere mounted on a robust 2.00 inch (50.8 mm diameter by 2-1/2 inch (63.5 mm) high steel post. The surface area of this sphere is four times as great as the area of the standard 1.00 inch sphere. The surface area of a 1.00 inch (25.4 mm) sphere is 3.1416 square inches (79.797 square mm) and the surface area of the 2.00 inch (50.8 mm) diameter sphere is 12.566 square inches (319.18 square mm).
The 4.00 inch (101.6 mm) diameter Magnetic Platform (Part Number M-PLT-4) is 1-1/2 inch (38.1 mm) thick and weighs over 5 lbs. (2.27 kg).
A rare earth magnet provides a holding force of over 100 pounds (45.358 kg).
Two pass-tipped jack screws are provided to assist in removing this powerful platform from the machine surface. As the jack screws are advanced, the soft pass tips press against the machine surface and smoothly raise the magnetic platform.
It is provided with a 3/8 inch by 16 threads per inch tapped hole in the center of the top surface and one near the outer edge. These threaded holes on the device are used to rigidly couple the various apparatus used with the platform.
The top surface of the magnetic platform is machinable, so that additional threaded holes or other details can be added for specific applications. We will provide prompt delivery of special machined details to your specifications.
The device is provided with an attractive black oxide finish that resists corrosion.
The 45 degree angle block ( Part Number BLK-45, Technical Data Sheet CMM-11) and both the three inch ( 3.00", 76.2mm ) long ( part Number P-EP-3 ) and the six inch (6.00", 152.4 mm) long (Part Number P-EP-6 ), 1-1/4 inch ( 1.25", 31.75 mm ) diameter extension posts are compatible with this platform. Both the 3.00 inch (76.2 mm) long (Part Number BO-EP-3), and the 6.00 inch (152.4 mm ) long (Part Number BO-EP-3 ) 2 inch (50.8 mm) diameter extension posts are also compatible with this platform.
| Part # | Description | Price | Purchase |
| M-PLT-4 | PLATFORM, MAGNETIC, 4" ( 101.6 MM ) DIAMETER, 1.5" ( 38.1 MM ) THICK | $276.00 | |
The 4 inch platform ( part number PLT-4 ) is a universal mounting tool. It is used to securely couple a variety of measuring devices to the machine under test. Among these devices are all of the CMM probe characterizing spheres on a post including the Mini Ball Bar (Dumbbell) ™ (see Technical Data Sheets CMM-7 and CMM-9).
The 45 degree Angle block (Part Number BLK 45) is designed for use with the four inch ( 101.6 mm ) platform . For performance evaluation of Computer Numerically Controlled machining centers, it will hold the standard 1.00 inch ( 25.4 mm ), part number PM-UB-B100, diameter Ultra Precise Test Sphere on the 1-1/4 inch (31.75 mm ) diameter post. It will also hold "The Big One", a two inch ( 50.8 mm ) diameter Test Sphere mounted on a 2 inch (50.8 mm) diameter by 2-1/2 inch (63.5 mm ) high post (Part Number PM-PB-B200).
All of these tools are coupled to the platform through a M10 x 1.5 diameter threaded stud. The platform has a tapped hole directly in the center and one near the outer edge of the top face. All of the accessories have corresponding tapped holes in them.
In addition to the central tapped hole, there are three 1/4 inch ( 6.35 mm ) diameter holes drilled through the platform and counter bored from the bottom. These three holes form the vertices of an equilateral triangle. They are used to mount three 3/4 inch ( 19.05 mm ) diameter truncated and tapped spheres to form the three Ball Kinematic Platform ( Part Number 3B-KM, Technical Data Sheet CMM-4) used in Ball Bar (Dumbbell) evaluation of Coordinate Measuring Machines.
This platform is manufactured from a free machining low alloy carbon steel. It may be easily modified to provide extra holes, threads, or other details. Prompt delivery of any modified configuration will be supplied at reasonable cost.
This robust steel platform is four inches ( 101.6 mm ) diameter and 1-1/2 inch ( 38.1 mm ) thick. It weighs over five pounds ( 2.27 kg ).
There is a recess machined in its base that leaves an annular ring around the edge. This ring is precision lapped flat to form an excellent coupling to a CMM or machine tool table.
There is a drilled and counter bored hole through the platform that will accept a 3/8 inch or a 10mm diameter socket head cap screw. This screw will securely clamp the platform to its mating surface.
The 4" platform is supplied with an attractive black oxide finish which helps to retard corrosion. Other finishes are available on special order.
| Part # | Description | Price | Purchase |
| PLT-4 | PLATFORM, 4 INCHES | $123.33 | |
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The Geostep™, model 3400-10, has ten ultra precise spheres permanently mounted on the centerline of a very rigid beam. This one universal tool is the only device required to fully calibrate most Coordinate Measuring Machines. After the Geostep™ 10 is properly calibrated, it becomes a fully traceable secondary standard. In addition to its ability to perform a full-scale machine calibration, the Geostep™10 will do an interim or Monday morning evaluation of the machine in just a matter of minutes. |
When trouble shooting to locate problems that occur with the machine's performance, the data collected from the simple in line design of the Geostep™10 are very easy for the calibration technician to interpret.
The unique three-dimensional characteristic of the spherical artifacts used on the Geostep™10 make them the ideal geometry for C.M.M. evaluation. There are no flatness or parallelism errors. There are no alignment or cosine errors of either the artifact or its positioning on the machine. This is because the origin of the spherical surface is perfectly defined by its radius as a single infinitely small address in three-dimensional space.
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The Geostep™10 is a Ball Plate. It is a Ball Bar (Dumbbell). It is a step standard.
It weighs only 20 pounds (9.0 kg), but the unique design makes it extremely rigid. All of the spherical artifacts are arranged on the center line or neutral bending plane of the beam. Any minute bending that does occur due to gravitational attraction or probing force will cause only very small second order cosine errors in the true position of the spherical artifacts.
The beam or frame of the device is produced by the special Stable Cast™ process. This near net shape process creates a metallurgically sound structure with very little retained austenite, so that its long term dimensional stability is assured.
The rugged beam of the Geostep™10 is 1.5 inches (38.1mm) thick and 4.0 inches (101.6mm) wide. The overall sphere center to sphere center dimension is approximately 850mm or (33.46 inches). The substantial reach of the Geostep™10 is more than twice that of a standard 400mm (15.75 inches) Ball Plate. A single technician can do the entire set up and calibration of the machine, because the Geostep™10 has a weight of less than 20 pounds (9 kg).
Each of the ten sphere center to sphere center dimensions are approximately 85mm or (3.34 inches) apart. These ten spheres provide 45 sphere center to sphere center dimensions. These center to center dimensions are intentionally varied from sphere to sphere. This feature is used to prevent any possible systematic errors in the scale system from falling into a matching pattern with the step standard. The ten 0.748 inch (19mm) diameter reference spheres are exactly the same diameter and spherical within less than 5 microinches (.13 micro meter). The standard spheres are produced from extremely fine grain, stainless steel that is hardened to 58 HRC and is thermally treated for long term dimensional stability. We also offer fine grain, high-density ceramic spheres.
The important feature of the particular ceramic used is that it has the same stiffness as steel, so that the calibration is not distorted due to differential elastic deformation. The extremely large 3.00 inch diameter window around the master spheres gives more than enough pretravel of the measuring probe to produce very reliable measurements on any make of Coordinate.Measuring Machine. A standard ball plate with 25 balls, has 300 potential sphere center to sphere center addresses. The Geostep™10 has 45. The number of addresses is very important because you need enough to do a good machine evaluation, but the yearly calibration of too many addresses becomes a very expensive proposition indeed.
The Geostep™10 can be used to characterize (calibrate) the test probe. It can be used to perform the repeatability test, and it is extremely well suited to evaluate the temperature drift effect.
The rugged universal holding device used to locate the Geostep™10 on the C.M.M. table can rigidly position it for vertical horizontal or angular probing. This holding device is based on our well-proven Anchor line of Ball Bar (Dumbbell) support devices. It consists of a rugged 3.0-inch (76mm) diameter steel post with a kinematically coupled tie down bulkhead. The upper structure provides full three degrees of freedom positioning of the Geostep™10. It can be rotated the full 360 degrees horizontally. It can articulate the full 180 degrees vertically and the Geostepª10 can rotate the full 360 degrees on its own axis.
A special kinematically coupled base plate, Part Number 3400-10, is available as an accessory to achieve the very low horizontal positions.
Optionally, the Geostep 10 can have one rail lapped straight within less than one micrometer (40 microinches). This is a popular device for evaluating "Z" axis roll. To add this feature, order the Geostep™3400-10.
The Geostep™10 will evaluate every one of the twenty one ( 21 ) theoretical C.M.M. rigid body errors. These include the accuracies of the X, Y and Z scales, the straightness of the X, Y and Z movements, the squareness of the X, Y and Z movements, each one of the three rotational errors that can occur in each one of the three axii.
In addition to measuring these 21 straight forward geometry and scale errors, the Geostep™10 will quantify the effect of the flexing or bending of the machine's mechanical structure, so that realistic measurement uncertainty can be assigned to the machine.
The Geostep 8 is simply a shorter version of the basic Geostep™, model 3400-10, it has eight spheres. The beam of the device is the standard one and one half inch (38.1mm) thick by 4 inch (101.6mm) wide. It has an overall sphere center to sphere center of 26.625 inches (676.3mm). This smaller device is equipped with a stand of appropriate height. There is a special accessory base plate, Part # BP-2600-8, used to achieve the low horizontals.
The Geostep 6 is a shorter version of the model 3400-10, it has six spheres. The overall sphere center to sphere center is 16.687 inches (424mm). This shortest version of the Geostep™ is equipped with a stand of appropriate height. The accessory plate for achieving the low horizontals for the Model 6 is Part # BP-1600-6.
| Part # | Description | Price | Purchase |
| GEOSTEP 3400-10 | GEOSTEP 3400-10 | $4800.00 | |
| GEO-LHKS | GEOSTEP, LOW HORIZONTAL KINEMATIC SUPPORT | $350.00 | |
| GEO-LSE | GEOSTEP, LAPPED STRAIGHT EDGE OPTION | $350.00 | |
| 1600-6 | GEOSTEP, SIX SPHERES | $4800.00 | |
| 2600-8 | GEOSTEP, EIGHT SPHERES | $4800.00 | |
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The contact probing system of a Coordinate Measuring Machine is characterized by evaluating a large number of measurements on the surface of a very precise sphere of known diameter. This precise sphere must be rigidly supported and held in a fixed position during the probe characterization process, otherwise misleading data will be collected (see Technical Data Sheet CMM-7 for Standard Characterization Spheres). This rigid support unavoidably covers up part of the spherical surface, which is therefore hidden from measurement by the contact probe. This hidden area is of no consequence when working with vertical probes, but it is of prime importance when the probe is inclined, horizontal or of compound, i.e. star design. The simple solution to this problem is to use the Ball Bar (Dumbbell) concept as developed many years ago. This device uses two very precise spheres of exactly the same known diameter which are securely mounted on opposite ends of a rigid bar. This hidden area on the first sphere is exactly 180 degrees from the hidden area on the second, so 100% of the spherical surfaces are in effect available for probing. |
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Mini Ball Bar (Dumbbell)™
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The distance between the centers of the two spheres is absolutely constant. In effect, a measurement made on one sphere is exactly the same as a measurement made on the opposite sphere minus the fixed distance between the two centers.
The Mini Ball Bar (Dumbbell) is a versatile version of this device. It is offered in four standard spherical diameters - 1.00 inch (25.4mm) Part #MBB-100, .750 inch (19.05mm) MBB-75, 0.500 inch (12.7mm) MBB-50, and 10mm (0.3937 inch) MBB-39. Custom diameter spheres or combinations of two different spheres on the same Ball Bar (Dumbbell) will be quickly supplied at reasonable cost.
The Ultra-Precise Calibration spheres on the three larger diameter versions are produced from very fine-grained, high chrome, high carbon, stainless steel. They are hardened to 58 Rockwell C for wear resistance and ultra cold cycled for long term dimensional stability. The 10 mm (0.3937 inch) sphere is made from micro grain tungsten carbide. It is dimensionally stable, very corrosion resistant, and it is much more rigid and wear resistant than steel.
The 1/8 inch (0.125", 3.175mm) diameter shaft used to mount the two ultra-precise spheres is made of tungsten carbide. Because this very rigid material allows such a small diameter shaft to be employed, the maximum area of the spherical surface is exposed for measurement. It would require a steel shaft of .408 inch (10.36mm) diameter to match its rigidity.
The incline position of the Mini Ball Bar (Dumbbell) is adjustable through a broad angular range. In this way, the ideal position to match each probe configuration can be used. The bar can be quickly switched to the opposite side of the post so that compound, i.e. star probes can be accommodated without relocating the base. The 1-1/4 inch(1.25", 31.75mm) diameter by 4 inch (101.6mm) high rugged steel post has an M10 X 1.5 threaded hole in its base to fasten it to a mating surface.
A three inch (76.2mm) long by 1-1/4 inch (31.75mm) diameter extension post (Part# P-EP-3) and a 6" inch long extension post (Part # P-EP-6) are available to raise the height of the Mini Ball Bar (Dumbbell) when characterizing star probes with long vertical members.
The rugged steel post that carries the Mini Ball Bar (Dumbbell) is coupled to the C.M.M. table through a robust steel platform (Part# PLT-4) (see Technical Data Sheet CMM-6.A.). This platform is four inches (101.6mm) diameter by 1-1/2 inch (38.1mm) thick and weighs over five pounds (2.27kg). The bottom of this platform is machined to leave an annular ring around the outside. This ring is precision lapped flat to provide a very stable connection with the top of the C.M.M. table. An M10 x1.5 threaded hole through the center of the platform allows the post to be securely clamped to the platform.
Another accessory available for use with the Mini Ball Bar (Dumbbell) is the 45 degree Angle Block (Part# BLK-45) which is used to incline the sphere and post at an angle for easier access.
In order to facilitate the connection and removal of the posts and extensions, a 3/16 inch (4.76mm) diameter clearance hole through the parts is provided. A removable steel pin made of high-tinsel stainless steel is supplied as a handle.
An attractive black oxide finish is applied to the post and other accessories to help prevent corrosion.
| Part # | Description | Price | Purchase |
| MBB-39 | MINI BALL BAR, 10 MM, 0.3937 INCHES | $352.63 | |
| MBB-50 | MINI BALL BAR, 12.7 MM, 0.5 INCHES | $352.63 | |
| MBB-75 | MINI BALL BAR, 19.05 MM, 0.75 INCHES | $352.63 | |
| MBB-100 | MINI BALL BAR, 25.4 MM, 1 INCHES | $352.63 | |
Specification Files |
Solidworks Files ( .SLDPRT ) |
| PM-PB-B75 / PM-UB-B75 |
| PM-PB-B100 / PM-UB-B100 |
| PM-PB-B75R / PM-UB-B75R |
| PM-PB-B100R / PM-UB-B100R |
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The 10mm (0.3937") (Part number PM-UB-B 39) sphere is made of micro-grained tungsten carbide and is mounted on a 0.125 inch (3.175mm) diameter tungsten carbide stem that is 0.850 inch (21.59mm) long.
This allows much greater measuring access to this smaller diameter sphere. The extremely high rigidity of tungsten carbide greatly reduces the elastic deformation of the smaller diameter sphere by the probe contact force, and yields a reduced bending moment of the support stem. Tungsten carbide is orders of magnitude more wear-resistant than hard steel. This material is very corrosion resistant, it will not rust.
The maximum departure from a perfect geometry on all of these spheres is 2.5 micro inches (63.5 nm). This tolerance is considered to be the limit of commercial metrology. This is twice as accurate as the quality requirements for "Performance Evaluation of Coordinate Measuring Machines ANSI/ASME-B89.4.1-1997" and ten times as good as high quality bearing balls. The specific size of all of these balls is held to a tolerance of +0.000020" (508nm). The quality of the surface texture is maintained below 0.5 micro inches (12.7nm) Ra. Spheres of this quality are simply not available from any other commercial source.
In keeping with the very rugged design, the ball is not simply glued on top of the post, but is reinforced by a long metal pin that penetrates deep inside the ball and the post so that a minor tap will not send the ball rolling across the room. This hole is drilled in the ball using special computer-controlled Electrical Discharge Machining (EDM) techniques which do not disturb the original quality of the balls.
For maximum stability, the post of the probe characterizing sphere is supported by a robust steel platform.
The post that supports the Ultra Precise Sphere and connects it to the platform is of rugged steel construction measuring 1-1/4 inch ( 1.25", 31.75 mm ) diameter at the base by 2-3/8 inch ( 2.375", 60.33 mm ) long.
The extremely robust 4 inch ( 101.6mm ) diameter, 1-1/2 inch ( 1.5", 38.1 mm ) thick steel platform (Part Number PLT-4 see Technical Data Sheet 6.A.) is used to couple the characterizing sphere to the CMM table.
The central portion of the bottom of this platform is relieved to provide an anular ring of contact. The surface of this ring is precision lapped flat to provide the most stable location possible with the measuring machine table. This robust 5.2 pound ( 2.3 kg ) assembly has a counter-bored tie-down hole provided for either a 3/8 inch ( .375", 9.525 mm ) or a 10mm diameter socket head cap screw.
In order to facilitate the connection and removal of the post, a 3/16 inch ( .1875", 4.76 mm) diameter clearance hole through the post is provided. A removable pin made of high tensile stainless steel is supplied as a handle.
Some accessories which are available for use with the probe characterizing spheres include a 45 Angle Block (Part Number BLK-45) used to incline the sphere and post at an angle for easier access. A 1-1/4 inch ( 1.25", 31.77 mm ) diameter by 3 inch ( 76.2mm ) long extension post (Part Number P-EP3) and 6 inch ( 152.4 mm ) long extension post (Part Number P-EP6) can be used to extend the height of the Probe Characterizing Spheres.
| Part # | Ball Diameter | Ball Material | |
| Click link for IGES file | |||
| 19.0500 mm | 0.7500" |
Hardened Stainless Steel |
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| 25.4001 mm | 1.0000" |
Hardened Stainless Steel |
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PM-UB-B39 |
10.0000 mm | 0.3937" |
Tungsten Carbide |
PM-UB-B50 |
12.7000 mm | 0.5000" |
Hardened Stainless Steel |
PM-UB-B75 |
19.0500 mm | 0.7500" |
Hardened Stainless Steel |
PM-UB-B100 |
25.4001 mm | 1.0000" |
Hardened Stainless Steel |
| 25.4001 mm | 1.0000" |
Hardened Stainless Steel, The Runt |
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PM-SAT-B50 |
12.7000 mm | 0.5000" |
Hardened Stainless Steel |
PM-SAT-B75 |
19.0500 mm | 0.7500" |
Hardened Stainless Steel |
PM-SAT-B100 |
25.4001 mm | 1.0000" |
Hardened Stainless Steel |
PM-SAT-B100-C |
25.4001 mm | 1.0000" |
Ceramic |
PM-SAT-B100-SN |
25.4001 mm | 1.0000" |
Silicon Nitride |
PM-SAT-B100-AO |
25.4001 mm | 1.0000" |
Aluminum Oxide |
PM-SAT-B100 -ZO |
25.4001 mm | 1.0000" |
Zirconium Oxide |
| Post Length - 2.375" (60.33 mm), Post Diameter - 1.250" (31.75 mm) | |||
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| Part # | Description | Price | Purchase |
| PM-PB-B100 | PROBE CHARACTERIZATION SPHERE, STAINLESS STEEL, 25.4 MM, 1 INCHES | $178.73 | |
| PM-PB-B100-AO-R | PROBE CHARACTERIZATION SPHERE, RUNT, ALUMINUM OXIDE, 25.4 MM, 1.00 INCHES | $178.73 | |
| PM-PB-B100-C-R | PROBE CHARACTERIZATION SPHERE, RUNT, CERAMIC, 25.4 MM, 1 INCHES | $178.73 | |
| PM-PB-B100-R | PROBE CHARACTERIZATION SPHERE, RUNT, STAINLESS STEEL, 25.4 MM, 1 INCHES | $178.73 | |
| PM-PB-B75 | PROBE CHARACTERIZATION SPHERE, STAINLESS STEEL, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-PB-B75-C | PROBE CHARACTERIZATION SPHERE, CERAMIC, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-PB-B75-C-R | PROBE CHARACTERIZATION SPHERE, RUNT, CERAMIC, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-PB-B75-R | PROBE CHARACTERIZATION SPHERE, RUNT, STAINLESS STEEL, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-SAT-B100 | PROBE CHARACTERIZATION SPHERE, SATIN FINISH, 25.4 MM, 1 INCHES | $178.73 | |
| PM-SAT-B100-AO | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 25.4 MM, 1.0 INCH, ALUMINUM OXIDE | $185.34 | |
| PM-SAT-B100-C | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 25.4 MM, 1 INCH, CERAMIC | $185.34 | |
| PM-SAT-B100-R | PROBE CHARACTERIZATION SPHERE, RUNT, SATIN FINISH, 25.4 MM, 1.0 INCHES | $178.73 | |
| PM-SAT-B50-R | PROBE CHARACTERIZATION SPHERE, RUNT, SATIN FINISH, 12.7 MM, 0.5 INCHES | $178.73 | |
| PM-SAT-B75 | PROBE CHARACTERIZATION SPHERE, SATIN FINISH, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-SAT-B75-R | PROBE CHARACTERIZATION SPHERE, RUNT, SATIN FINISH, 19.05 MM, 0.75 INCHES | $178.73 | |
| PM-SLM-UB-B100 | PROBE CALIBRATION SPHERE, SLIM, 25.4 MM, 1.00 INCHES | $182.42 | |
| PM-SLM-UB-B39 | PROBE CALIBRATION SPHERE, SLIM, 10 MM, 0.3937 INCHES | $199.45 | |
| PM-SLM-UB-B50 | PROBE CALIBRATION SPHERE, SLIM, 12.7 MM, 0.5 INCHES | $182.42 | |
| PM-SLM-UB-B75 | PROBE CALIBRATION SPHERE, SLIM, 19.05 MM, 0.75 INCHES | $182.42 | |
| PM-STAR-100 | STAR PROBE CALIBRATION ARTIFACT WITH 1.00" BALLS | $685.00 | |
| PM-STAR-75 | STAR PROBE CALIBRATION ARTIFACT WITH 0.75" BALLS | $585.00 | |
| PM-UB-B100 | PROBE CHARACTERIZATION SPHERE, ULTRA PRECISE, 25.4 MM, 1 INCHES | $198.77 | |
| PM-UB-B100R | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 25.4 MM, 1.0 INCH | $198.77 | |
| PM-UB-B39-R | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 10 MM, 0.393 INCHES | $198.77 | |
| PM-UB-B50 | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 12.7 MM, 0.5 INCHES | $198.77 | |
| PM-UB-B50-R | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 12.7 MM, 0.5 INCHES | $198.77 | |
| PM-UB-B75 | PROBE CHARACTERIZATION SPHERE, ULTRA PRECISE, 19.05 MM, 0.75 INCHES | $198.77 | |
| PM-UB-B75-R | PROBE CHARACTERIZATION SPHERE, RUNT, ULTRA PRECISE, 19.05 MM, 0.75 INCHES | $198.77 | |
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The Runt™ fills the need for a shorter, more petite, probe characterization sphere for smaller Coordinate Measuring Machines ( CMM ) and for other special applications. The standard spherical diameter of the master ball is one inch (1.00", 25.4 mm ). The Runt™ is also available in a wide range of master ball diameters of both English and metric sizes to satisfy all requirements. |
 Solidworks rendering of the Runt |
The overall height of the Runt™ equipped with a 1.00 inch ( 25.4mm ) diameter sphere is only 2 3/8 inch ( 2.375", 60.3 mm), which is a full inch shorter than the standard versions. Although manufactured to the highest quality standards the Runt™ is sold for a very reasonable price. The quality of the sphere for the standard version of the Runt (Part Number PM-PB-B100-R) is held to a five microinch (127mm) sphericity which meets the quality requirements for the.revised ANSI-B89.4.1- 1997 specification for the "Performance Evaluation of Coordinate.Measuring Machines". The quality of the sphere for the Ultra Precision version of the Runt™ (Part Number PM-UB-B100-R) is two and one half microinch ( 63.5nm ) sphericity which is state of the art for calibrating the test probes of the highest quality machines. |
In keeping with the very rugged design, the ball is not simply glued on top of the post, but is reinforced by a long metal pin that penetrates deep inside the ball and the post so that a minor tap will not send the ball rolling across the room. This hole is drilled in the ball by using special computer controlled Electrical Machining (EDM) technique which does not disturb the original quality of the ball.
There is an MlOX1.5 threaded hole, in the base of the Runt™, which is used to rigidly fasten it to any mating surface.
Through the use of our Dual Threaded Adapter Screws, (see Technical Data Sheet CMM-14 Table #1.) it can be adapted to the thread size of any C.M.M. table.
The Runt™ is compatible with the standard 1 1/4 inch ( 31.75 mm) diameter extensions of either the 3 inch (7.6 cm) long (Part# P-EP-3) or the 6 inch (15.2cm) long (Part# P-EP-6) (see Technical Data Sheet CMM-12.) the four inch diameter Platform, (Part# PLT-4) (see Technical Data Sheet CMM-6A.) the four inch diameter Magnetic Platform (Part# M-PLT-4) (see Technical Data Sheet CNC-2.) or on the Abalone vacuum chuck (Part# 10140)(see Technical Data Sheet CMM-13, Page 1.).
There is a 3/16 inch (4.8mm) diameter hole drilled at right angles through the post of the Runt™. A pin placed through this hole is used as a wrench to rotate the post to securely tighten or remove it.
Except for the shorter overall length, this device has the same characteristics as the standard version of the post mounted calibration spheres (see Technical Data Sheet CMM-7 Page1 and 2.)
See the above page for pricing.
| Part # | Ball Diameter | Ball Material | |
| Click link for IGES file | |||
| 25.4001 mm | 1.0000" |
Hardened Stainless Steel, The Runt |
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| Post Length - 2.375" (60.33 mm), Post Diameter - 1.250" (31.75 mm) | |||
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Specification Files
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Part No: PM-STAR-75 Shown with Six Inch Steel Ruler |
As the C.M.M. probes get more and more complex, the difficulty and complexity of calibrating them becomes more acute. A typical star probe has five probe spheres that must all be characterized in order to fully utilize the probe. In order to reach around, over and under all of these spherical contacts without moving the calibration sphere all over the place; a multi-sphere artifact must be used. *Note that the platform shown, PLT-4, is included. By utilizing a set of five exactly matched calibration spheres that are arranged on orthogonal planes, this job can be done with relative ease. By building one ultra precise, ultra rigid universal artifact that can be used for calibrating even the most complex star probes; we have arrived at an economical approach to this dilemma. Many different diameter spherical artifacts can be used; but the most popular are three quarters of an inch 0.750 ( 19.05mm ) and one inch 1.00 ( 25.4mm ). |
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The spheres are normally produced from a very high chrome, high carbon Martensitic stainless steel. This ultra fine-grained material is through hardened to 58 HRC (Hardness on the Rockwell "C" scale) minimum. The material is subjected to a three cycle thermal stabilizing process to assure long-term dimensional stability. The sphericity and common size of the balls used on this artifact are held with five microinches (127 nanometers) with a 0.40 microinch (10 nanometers) Ra surface finish. The Young's Modulus of elasticity, or stiffness of these spheres is the same as that of steel parts, so that the highest level of measuring accuracy can be achieved.
This device is also available with ultra precise ceramic balls instead of steel.
For calibrating various optical probes it is also available with satin finished steel, titanium, or ceramic balls.
These optical target balls form a 3D artifact that is effective in evaluating the performance of the optical probe.
| Part # | Description | Price | Purchase |
| PM-STAR-75 | STAR PROBE CALIBRATION ARTIFACT WITH 0.75" BALLS | $585.00 | |
| PM-STAR-100 | STAR PROBE CALIBRATION ARTIFACT WITH 1.00" BALLS | $685.00 | |
 Characterization sphere shown with an inch ruler for scale |
For calibrating standard vertical or horizontal C.M.M. probes, our long time standard probe calibration sphere, part number PM-PB-B100 is the best inexpensive solution. When you must calibrate complex star probes or articulating probes, the long time standard probe calibration sphere comes up lacking; because the large rigid post we use covers up too much of the area of the probe calibration sphere. Most competitive companies have tried to solve this problem by using small diameter offset posts. This approach causes more problems than it solves. This is especially true when these posts are made of very low stiffness stainless steel. The bending of this spindly post by the probing force causes the sphere to measure much smaller than it really is. When the probe is compensated, using the true diameter of the calibration sphere, a substantial error is built into every future measurement. The Slim Calibration Sphere solves these problems quite nicely. This is done by mounting the probe calibration sphere on a very small diameter rod of an extremely rigid material. |
By using this very simple fundamental of physics, we get excellent accessibility without the elastic deflection caused by the probing force. By building the support rod from a material that is almost four times as stiff as hardened steel, our one eighth of an inch diameter ( 3.175 mm ) support rod is equivalent to a .400-inch ( 10.16 mm) diameter steel post.
The rugged one and one quarter inch (31.75 mm) diameter construction of the Slim Calibration Sphere base is compatible with all of our probe sphere hardware. This includes all extensions, bases and the 45-degree block. It is held in place by a large M10 X 1.5 (over 3/8 inch) socket head cap screw. This arrangement allows the sphere or spheres to be rotated into the ideal position for probing before locking the assembly down.
The simplest version of the Slim Calibration Sphere (our part number PM-SLM-) followed by the desired diameter of the calibration sphere required (1 inch, 20 mm, .5 inch, 10 mm etc.), at a cost of between $182.42 and $199.45 each.
The simplest design has a single master sphere mounted at 45 degrees on a one-inch (25.4 mm) long, one eighth of an inch (1/8", 0.125", 3.175 mm) diameter extremely stiff rod.
This device is also available with up to four calibration spheres mounted simultaneously. Simply specify the diameters of the desired spheres when ordering (each additional sphere costs $86.19 each). The calibration spheres can all be of the same diameter, or they can be of different diameters.
In very sophisticated C.M.M. Systems, two master spheres of exactly the same diameter, located 180 degrees apart, are used to calibrate the probe. The distance between the two spheres is fixed, so it can be subtracted when both spheres are probed. In this way the area where the post is located does not subtract anything from the characterization of the probe.
When calibrating really small diameter probing tips, there is
a distinct advantage in using a much smaller diameter probe
calibration sphere. For these applications a 10 mm (.3937 inches)
or three eighths of an inch (9.53 mm) sphere is the usual choice.
Because these small diameter spheres are so easily damaged, they
are normally constructed of cemented tungsten carbide.
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The Tri-mount TM Ball Bar (Dumbbell) collar is a recent improvement in the tools for Coordinate Measuring Machine evaluation. The fundamental design of the Tri-mount allows it to hold three or more separate Ball Bar (Dumbbell)s all at the same time. The Tri-mount (Part #FS-3) is used with the Heavy Duty Stand (Part #FS-14, FS-24 or FS-36). The Tri-mount (Part #AN-3) is used with the Anchor (Part #AN-8, AN-12 or AN-24) when small size or light weight are important. This device meets all of the requirements for the "Performance Evaluation of Coordinate Measuring Machines" according to the ANSI B89.4.1-1997 specification. |
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A unique feature of this new device is that it totally eliminates any hand contact with the Ball Bar (Dumbbell) by the calibration technician. This is especially important because all Ball Bar (Dumbbell)s are rather long devices which make them very sensitive to temperature change.
There are 20 basic Ball Bar (Dumbbell) positions according to the ANSI B89.4.1-1997 specification. Some of them have the Ball Bar (Dumbbell) horizontal, some have it vertical and some have it at an angle usually approaching 45 degrees.
For longer or wider machined, some of these 20 basic positions are repeated and over-lapped so we may end up with 30 or even 35 positions. The Tri-mount allows all of the positions to be met without once touching the ball bar itself.
The same standard Heavy Duty Stand or Anchor and the Tri-mount hardware can be used over a broad range of C.M.M. sizes by just substituting different lengths of Ball Bars.
The Tri-mount collar (Part #FS-3 or AN-3) is compatible with any of our existing equipment so you can easily update at very reasonable cost. The location ports on the Tri-mount will accept the Single Ball Bar (Dumbbell) clamp (Part #FS-1BB) and the Dual Ball Bar (Dumbbell) clamp (Part # FS-2BB) or any length of the Way Out Ball Bar (Dumbbell) supports (see Technical Data Sheet C.M.M.-16, Page 2.) and Cantilever Ball Bar (Dumbbell)s (see Technical Data Sheet C.M.M.-16, Page 1.).
| Part # | Description | Price | Purchase |
| AN-3 | COLLAR, 3 INCH TRI-MOUNT, FOR THE MAMMOTH | $223.97 | |
| FS-3 | TRI-MOUNT COLLAR | $213.97 | |
| FS-3BB | TRI-MOUNT COLLAR AND THREE SINGLE BALL BAR CLAMPS | $548.83 | |
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Part No.: INDTRI14
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This lightweight device, a trivet, is designed to provide precise, repeatable, indexing of the "Geostep" (see "Geostep" technical data sheet) or other C.M.M. calibration devices. Most of the hardware used in this setup are part of our off the shelf line of components. By using these standard components, this rather sophisticated device can be produced for a very modest cost. Our standard "14-inch Trivet" is modified to become the upper rotating half of this Kinematically positioned indexing system. The indexing lever is simply rotated 90°, to raise the "Trivet". The "Trivet" is then indexed to the next position. When the lever is returned to its original position, it lowers the "Trivet" onto the Kinematic spheres of its new orientation and the next measurements can be made. This system provides six precise, repeatable positions. They start at 0° then to 60° then 120° then 180° then 240° then 300° and then back to zero, or 360°.
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 The 14" Indexing Trivit |
The calibration device or devices used for the C.M.M. evaluation are held in position at the desired height by using the ideal height of "Anchor" (see the "Anchor" technical data sheet in the C.M.M. catalog, for the standard heights available).
To hold the "Geostep" in perfect position, the "Geoclamp" is attached to the top of the "Anchor" and the "Geostep" is installed between the two parallel clamping plates. In order to keep the weight of the "Geoclamp" to a minimum it is constructed almost entirely of aluminum.
The circular base of this system forms a truly Kinematic indexing device. It is constructed of a lightweight, aircraft quality aluminum casting.
Twenty four ( 24 ) very precisely ground and lapped spherical components are rigidly fixed to give precise fifteen ( 15 ) degree increments in the top surface of the base casting. The upper half of the Kinematic indexing system consists of three pair of our standard split Kinematic vee blocks (see Split Vee Blocks technical data sheet under Kinematic products) that are rigidly mounted in three precision-machined trenches in the Trivet.
When working with automatic self-propelled C.M.M.'s, totally automatic measuring of the calibration artifacts can be achieved using the indexing Trivet.
With the twenty four spheres on the base ring, every twelfth sphere is 180 degrees apart. By measuring and aligning any two of the Kinematic spheres that are at 180 degrees to each other, with the "X" axis of the C.M.M., the position of the artifact will be aligned well enough for automatic re-measurement.
The material chosen for the vees and the spheres of the indexing Trivet is a very high chrome, high carbon, Martensitic stainless steel. This ultra fine-grained material is through hardened to 58 HRC (Hardness on the Rockwell "C" scale) minimum.
This indexing Trivet can also be supplied in custom configurations with orthogonal or other angular configurations.
| Part # | Description | Price | Purchase |
| INDTRI14 | TRIVET, 14 INCH, INDEXING | $770.00 | |
| TRI14 | TRIVET, 14 INCH, REGULAR | $400.00 | |
Trivet Pictures
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| IMG_0735.jpg | IMG_0736.jpg | IMG_0741.jpg | IMG_0742.jpg |
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| IMG_0744.jpg | IMG_0745.jpg | IMG_0747.jpg |
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The proper Steel pin, ( 0.125", 3.18 mm diameter ) is supplied with each of the UB* and PB* series spheres. For the UB-B39, a 0.125 inch (31.75 mm) diameter by 0.850 inch (21.59 mm ) long tungsten carbide pin is supplied.
| Part Number* |
A - Dimension Ball Diameter + 0.000020" (+500NM) |
B - Dimension + 0.010" -.000" (+0.127 mm) (-0.000 mm) |
C - Depth + 0.010" (+0.254 mm) |
Ball Sphericity |
Ball Surface Quality |
Ball Material |
Price | Purchase |
| UB-B39 | 0.3937" 10 mm |
0.130" (3.302 mm) |
0.150" (3.810 mm) |
0.0000025" (63.5 NM) |
0.0000005" Ra. (12.5 NM) |
Tungsten Carbide |
$86.00 | |
| UB-B50 | 0.500" 12.7 mm |
0.130" (3.302 mm |
0.150" (3.810 mm) |
0.0000025" (63.5 NM) |
0.0000005" Ra. (12.5 NM) |
Hardened Stainless Steel |
$86.00 | |
| PB-B50 SAT-B50 |
0.500" 12.7 mm |
0.130" (3.302 mm) |
0.150" (3.810 mm) |
0.0000025" (63.5 NM) |
0.0000005" Ra. (12.5 NM) |
Hardened Stainless Steel |
$61.69 | |
| $63.00 | |
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| UB-B75 | 0.750" 19.05 mm |
0.130" (3.302 mm) |
0.250" (6.35 mm) |
0.0000025" (63.5 NM) |
0.0000005" Ra. (12.5 NM) |
Hardened Stainless Steel |
$86.00 | |
| PB-B75 SAT-B75 |
0.750" 19.05 mm |
0.130" (3.302 mm) |
0.250" (6.35 mm) |
0.000005" (125 NM) |
0.0000007" Ra. (17.5 NM) |
Hardened Stainless Steel |
$63.00 | |
| $63.00 | |
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| UB-B100 | 1.00" 25.4 mm |
0.130" (3.302 mm) |
0.250" (6.35 mm) |
0.0000025" (63.5 NM) |
0.0000005" Ra. (12.5 NM) |
Hardened Stainless Steel |
$86.00 | |
| PB-B100 SAT-B100 |
1.00" 25.4 mm |
0.130" (3.302 mm) |
0.250" (6.35 mm) |
0.000005" (125 NM) |
0.0000007" Ra. (17.5 NM) |
Hardened Stainless Steel |
$62.69 | |
| $63.00 | |
http://www.precisionballs.com |
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