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RMA Standards for Cross Sectional Tolerance Table — Rubber Extrusions

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RMA Standards for Cross Sectional Tolerance Table — Rubber Extrusions

The closer tolerance classes outlined below should not be specified unless required to do so by the final application and they should be restricted to the critical dimensions. The closer tolerances demanded, the tighter the control must be exercised when the material is being extruded and hence the higher the cost incurred.

Dimensions in millimeters
RMA Class 1 – High Precision 2 – Precision 3 – Commercial
Drawing Designations E1 E2 E3
Above Up to
0 1.5 ±0.15 ±0.25 ±0.40
1.5 2.5 0.20 0.35 0.50
2.5 4.0 0.25 0.40 0.70
4.0 6.3 0.35 0.50 0.80
6.3 10.0 0.40 0.70 1.00
10.0 16.0 0.50 0.80 1.30
16.0 25.0 0.70 1.00 1.60
25.0 40.0 0.80 1.30 2.00
40.0 63.0 1.00 1.60 2.50
63.0 100.0 1.30 2.00 3.20
Dimensions in inches
RMA Class 1 – High Precision 2 – Precision 3 – Commercial
Drawing Designations E1 E2 E3
Above Up to
0.00 0.06 ±0.006 ±0.010 ±0.015
0.06 0.10 0.008 0.014 0.020
0.10 0.16 0.010 0.016 0.027
0.16 0.25 0.014 0.020 0.031
0.25 0.39 0.016 0.027 0.039
0.39 0.63 0.020 0.031 0.051
0.63 0.98 0.027 0.039 0.063
0.98 1.57 0.031 0.051 0.079
1.57 2.48 0.039 0.063 0.098
2.48 3.94 0.051 0.079 0.126

In general, softer materials and those requiring a post cure will need greater tolerances.