thread class options

[jeffsteiger6735]

Anyone know why the class 3A option is missing from  an ANSI unified screw thread, size 0.875, 7/8-14 UNF?

My only options from the class drop down are 1B, 2B, and 3B.

There should be a 3A option (or any A option) according to Fastenal:

• Classes 3A and 3B are suited for close tolerance fasteners. These fasteners are intended for service where safety is a critical design consideration. This class of fit has restrictive tolerances and no allowance. Socket products generally have a 3A thread fit.

[rush02112 · Accepted solution]

Check your thread excel sheet, check the cell for external>major Dia> Class and make sure it says 3A

[jeffsteiger6735]

Ahh of course. Thanks.