On Wed, 6 Jan 2010 14:42:16 -0500, "Existential Angst"
wrote:

Awl --

I got a hardware-store eye-bolt, 1/4-20, garden variety, not welded or cast.

The thread measures .246 -- no pro'leng.
But the part of the rod that forms the eye measures .210-.215.... !!

Shouldn't the eyebolt measure .246 *everywhere*?

Or did they form-thread .215 rod, with the threads now deformed out to
.246?
I figger that's gotta be the explanation?
I know about form tapping, just never heard of form-threading, which I
assume must exist.
==============
see
http://video.google.com/videosearch?...ed=0CDUQqwQwCQ
http://www.efunda.com/processes/meta...ad_rolling.cfm


The only problems are cosmetic in that the crests of the thread
may not not be perfect, but the crests don't effect the
functionality of the thread.
Unka George

(George McDuffee)

The past is a foreign country;
they do things differently there.
L. P. Hartley (1895-1972), British author.
The Go-Between, Prologue (1953).