Versatile Inspection Ball Kit
This inexpensive ball kit contains a wide variety of 98 non standard precision balls.
It consists of groups of special ball sizes centered around commonly used fractional inch
Balls. These ball sizes reflect the most frequently requested balls for inspection
applications.
Each group of seven balls contain a standard nominal fractional size ball as well as one
each of a +.002”, +.001”, +.0005”, +.0002”, and -.001”, -.002”.
The balls are precision lapped to meet the A.F.B.M.A. standard Grade25. They are
spherical within 25 millions of an inch (635 nm). The surface finish is below 1.5 micro inches
(38.1 nm) Ra and the exact ball size is within + or -.0001” of an inch (.00254 mm). The balls
are manufactured from chrome alloy steel that is hardened to 62 Rockwell C for wear
resistance. This material has a thermal coefficient of expansion equal to 6.3 micro inches
per inch per degree Fahrenheit or 11.4 micro meters per meter Centigrade. This matches
steel gage blocks and is the same as most iron and steel products.
This ball kit includes the 14 most popular fractional inch sizes from 3/32” (2.381 mm) to
1.0       inch to (25.4 mm).
Each of the 14 fractional groups of balls is packaged together in an individual plastic vial.
These plastic vials are housed in a very rugged plastic tray. This tray is placed a robust
steel shipping and storage case. This large steel case is 12 inches wide by 18 inches long
by 3 inches deep.
Part #	Nominal Size
BK-14	Full Kit of 14 Sizes From 3/32” – 1”	----
093-BK	3/32”	2.381 mm
125-BK	1/8”	3.175 mm
156-BK	5/32”	3.969 mm
187-BK	3/16”	4.763 mm
218-BK	7/32”	5.556 mm
250-BK	1/4”	6.35 mm
312-BK	5/16”	7.938 mm
375-BK	3/8”	9.525 mm
437-BK	7/16”	11.113 mm
500-BK	1/2”	12.7 mm
625-BK	5/8”	15.875 mm
750-BK	3/4”	19.05 mm
875-BK	7/8”	22.225 mm
100-BK	1”	25.4 mm
SO-PT	Sapphire Oil- 1 Pint	----
SO-GAL	Sapphire Oil- 1 Gallon	----