Paul W. Marino Gages, Inc.
102 NE Second Street, #407 | Boca Raton FL 33432 USA | Phone 800.528.9785 or 586.772.2400 |

American Modular Tooling | CMM Styli and Accessories | Request Catalogs | On Sale!

Your Shopping Cart

Styli Technical / Quality Data

A.F.B.M.A. Grade Tolerances and Terminology

A.F.B.M.A. Grade Diameter Tolerance, per Ball Sphericity Diameter Tolerance, per Unit Container Basic Diameter Tolerance Marking Increments
- Inch Inch Inch Inch
3 .000003 .000005 +/-.00003 .000003
5 .000005 .00001 +/-.00005 .000005
10 .000010 .00002 +/-.0001 .000010
15 .000015 .00003 +/-.0001 .000015
25 .000025 .00005 +/-.0001 .000025
50 .00005 .0001 +/-.0002 .00005
100 .0001 .0002 +/-.0005 .0001
200 .0002 .0004 +/-.0010 .0002

Grade: The numerical value of the Diameter Tolerance per Ball expressed in millionths of an inch
Diameter Tolerance per Ball: The permissible difference between the largest diameter and the smallest diameter measurable on one ball
Diameter Tolerance per Unit Container: The permissible range of the average diameters of the individual balls within any one unit container.
Basic Diameter: The size ordered which is the basis to which the basic diameter tolerances apply. The Basic Diameter is specified by a fraction plus a decimal or a decimal only to the sixth place, e.g. 1/4"+.0002" or .02502", 15-64"+.0003" or .234675".
Basic Diameter Tolerance: The maximum allowable deviation of any ball diameter from the basic diameter, in any shipments to fill orders for that basic diameter.
Marking Increments The standard unit steps in millionths of an inch used to express the Specific Diameter.

Technical Data

Item Material Form Deviation Diameter Tolerance Hardness (Vickers) Density (g/cm3) Surface Finish
Ruby Ball Synthetic ruby AL2O3, monocrystalline <0.25um +/-.025um 1800 3.9 0.015um
Hollow Ceramic Ball AL2O3, polycrystalline <0.6um +/-0.6um 1650 3.9 0.1um
Cylinder, Stainless Steel Stainless Steel <2um +/-10um 250 7.9 0.4um
Cylinder, Ruby Synthetic ruby AL2O3 <1um +/-1um 1800 3.9 0.05um
Cylinder, TC Tungsten Carbide <1um +/-1um 1550 15.0 0.2um
Ball Disc, Ceramic Alumina AL2O3, ceramic polycrystalline <0.6um +/-0.6um 1650 3.9 0.1um
Ball Disc, Steel Stainless Steel <3um +/-10um 250 7.9 0.4um
Disc Stylus, Steel Hardened Steel <2um +/-10um 720 7.9 0.2um
Shank and Extension, Stainless Steel Stainless Steel - - - 7.9 -
Shank and Extension, Ceramic Alumina AL2O3, ceramic polycrystalline - - - 3.9 -
Shank and Extension, Carbon Fiber Carbon Fiber - - - 1.5 -
Shank, Tungsten Carbide Tungsten Carbide - - - 15.0 -
Extension, Alu7075 7075 high strength aluminum Hard coat anodized surface with PTFE inserts 2.8 -