The following tables illustrate different levels of tolerance control for all elastomeric parts. However, these standard tables do not take into account specific design concerns such as allowable flash. For assistance, please contact Apple Rubber for specific recommendations.

RMA Designation “A1” High Precision

Drawing designation “A1” is the tightest tolerance classification and indicates a high precision product. Such products require expensive molds, fewer cavities per mold, costly in-process controls and inspection procedures. It is desirable that the exact method of measurement be agreed upon between rubber manufacturer and customer, as errors in measurement may be large in relation to the tolerance.

Size (Inches) Fixed Closure
Above Incl.  
0 - .40 ±.004 ±.005
.40 - .63 ±.005 ±.006
.63 - 1.00 ±.006 ±.008
1.00 - 1.60 ±.008 ±.010
1.60 - 2.50 ±.010 ±.013
2.50 - 4.00 ±.013 ±.016
4.00 - 6.30 ±.016 ±.020
Size (Millimeters) Fixed Closure
Above Incl.  
0 - 10 ±.10 ±.13
10 - 16 ±.13 ±.16
16 - 25 ±.16 ±.20
25 - 40 ±.20 ±.25
40 - 63 ±.25 ±.32
63 - 100 ±.32 ±.40
100 - 160 ±.40 ±.50

RMA Designation “A2” Precision

Drawing Designation “A2” tolerances indicate a precision product. Molds must be precision machined and kept in good repair. While measurement methods may be simpler than with Drawing Designation “A1", careful inspection will usually be required.

Size (Inches) Fixed Closure
Above Incl.  
0 - .40 ±.006 ±.008
.40 - .63 ±.008 ±.010
.63 - 1.00 ±.010 ±.013
1.00 - 1.60 ±.013 ±.016
1.60 - 2.50 ±.016 ±.020
2.50 - 4.00 ±.020 ±.025
4.00 - 6.30 ±.025 ±.032
6.30 & over
multiply by
±.004 ±.005
Size (Millimeters) Fixed Closure
Above Incl.  
0 - 10 ±.16 ±.20
10 - 16 ±.20 ±.25
16 - 25 ±.25 ±.32
25 - 40 ±.32 ±.40
40 - 63 ±.40 ±.50
63 - 100 ±.50 ±.63
100 - 160 ±.63 ±.80
160 & over mul ±.20 ±.25
160 & over
multiply by
±.004 ±.005

 

RMA Designation A2 Precision

Tables

Standard AS568 Size O-Rings
Standard O-Rings Boss Gaskets For Straight Thread Tube Fitting

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