RMA Dimensional Tolerances For Elastometic Parts (PDF)


"A2" Precision Drawing Designation
Dimensional Tolerance Table for Molded Rubber Products
Size (Millimeters) Size (Inches)
Above-
Included
Fixed Closure Above-
Included
Fixed Closure
0-10 +/-.16 +/-.20 0 - .40 +/-.006 +/-.008
10 - 16 .20 .25 .40 - .63 .008 .010
16 - 25 .25 .32 .63 - 1.00 .010 .013
25 - 40 .32 .40 1.00 -1 .60 .013 .016
40 - 63 .40 .50 1.60 - 2.50 .016 .020
63 -100 .50 .63 2.50 - 4.00 .020 .025
100 - 160 .63 .80 4.00 - 6.30 .025 .032
160 & over x .004 x .005 6.30 & over x .004 x .005
"A3" Commercial Drawing Designation
Dimensional Tolerance Table for Molded Rubber Products
Size (Millimeters) Size (Inches)
Above-
Included
Fixed Closure Above-
Included
Fixed Closure
0-10 +/-.20 +/-.32 0 - .40 +/-.008 +/-.013
10 - 16 .25 .40 .40 - .63 .010 .016
16 - 25 .32 .50 .63 - 1.00 .013 .020
25 - 40 .40 .63 1.00 -1 .60 .016 .025
40 - 63 .50 .80 1.60 - 2.50 .020 .032
63 -100 .63 1.00 2.50 - 4.00 .025 .040
100 - 160 .80 1.25 4.00 - 6.30 .032 .050
160 & over x .005 x .008 6.30 & over x .005 x .008
When applying tolerances, keep the following rules in mind:

  • Consider using the maximum possible tolerance on your product.

  • Regarding "A2" tolerances and t ighter, it is highly advisable to predetermine and agree upon a common method of measurement to reduce repeatability errors and rejected shipments.

  • It is often practical and wise to have a prototype cavity machined to evaluate the dimensional accuracy of the part you wish to manufacture. A much superior job of "dialing in" the desired final result can be accomplished using this method.


Cross-Sectional View of Rubber Mold