[TR] Replacement bolts

[Karl Vacek]

Don't know if any are used on a TR3, but there are also lots of other 
less-common sizes that are nonetheless standard too.  What you listed are 
the UNF/SAE fine threads, but here are the common 1/4" threads for which I 
have taps in my hand: 1/4-20 (UNC) 1/4-24 (USF), 1/4-28 (UNF/SAE), and 
1/4-32 (UNEF).  I couldn't find one glancing through my unorganized tap 
drawer without reading glasses, but I'd swear I have a 1/4-27 too.

In 5/16 I have 5/16-18 (UNC), 5/16-20 (USF), 5/16-24 (UNF/SAE), 5/16-27 
(this one is also marked USF !!??), and 5/16-32 (UNEF).

I may not have found all of them - because I had no reading glasses with me 
when I went to the garage to get them  ;-)  This pattern continues on up the 
sizes - not to mention the special threads used by some diabolical designer 
just because he could.  In larger sizes it's even more common to find other 
(mostly fine) thread pitches.

Then there's Whitworth (coarse) and British Standard (fine).  All different 
thread form (and 55 degree angle threads), different wrenches, etc.  And the 
same wrench is called one size in Whitworth and the next size up in BSF...

Karl

> NF (National Fine) specifies a different thread pitch for almost every
> different diameter (just as NC is different pitch for almost every
> diameter).  The common NF bolts on a TR3 (which I assume applies to a TR2 
> as
> well) are:
> 10-32
> 1/4-28
> 5/16-24
> 3/8-24
> 7/16-20
> 1/2-20
> 9/16-18
>
> -- Randall