If you *must* have tighter fitting fasteners, you may go to class 4 or
above, but that is rarely required.

Class 4 and above are undersized or closer tolerance taps, right? I was
going to suggest a slightly undersized tap for 1/4-20... I presume it is
the same thing?

Regards,
Joe Agro, Jr.
(800) 871-5022
http://www.AutoDrill.com
http://www.Multi-Drill.com

V8013