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Radial O-Ring Selector
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This calculator allows you to find the recommended O-Ring inner diameter and range of cross section diameters that will fit a given gland size and tolerance range in a radial seal.
  Bore diameter, Bd:    
  Bore Tolerance, Btol:    
  Groove Diameter, Gd:    
  Groove Tolerance, Gtol:    
  O-Ring maximum compression, Cmax:     %
  O-Ring minimum compression, Cmin:     %
  O-Ring cross-section diameter tolerance, CStol:    
  Max. cross-section diameter (excl. tol.), CSmax:  0.068  in
  Min. cross-section diameter (excl. tol.), CSmin:  0.065  in
  Your input CS tolerance, CStol:  0.003  in
  Industry-recommended CS tolerance:  0.003  in
  Recommended O-Ring inner diameter, IDrec:  0.392  in
  Suggested groove width, GW:  0.103  in
Equations Behind the Calculator
This calculator implements the following two equations to determine the bounds on the cross-section diameter CS,

The recommended tolerance is based on the cross-section diameter, and is found from the following table:

Cross Section Diameter
Recommended Tolerance
CS < 0.104 0.003
0.104 < CS < 0.139 0.004
0.139 < CS < 0.210 0.005
0.210 < CS < 0.275 0.006
0.275 < CS 0.008
The recommended inner diameter is found by stretching the O-Ring circumference by 2% over the minimum Groove Diameter,

The suggested groove width follows from,

More information is provided on the Design Guideline page.