Backrind is a torn or gouged condition (recess) at the mold parting line caused by thermal expansion over sharp mold edges or by premature cure.

Specification Max Allowable Backrind Width
Max Allowable Backrind Depth
AS708* Not Specified (.005 is standard reject for any defect) Not Specified
ISO 3601-3 CS 0
AS871 0
ISO 3601-3 S, DIN 3771 S .0039 .0020
ISO 3601-3 N, DIN 3771 N .0071 .0031
MIL-STD-413C 0
RMA OR-1 A 0
RMA OR-1 B .005 .003
Note: No tool marks or defects discernible to the naked eye are permitted.
**Data above shows maximum allowable Width/Depth of Backrind assuming an O-ring cross sectional diameter between 0 and .1 inches.

Backrind diagram