[SEL] Tap & Die Set Help Needed--OT

[Paul Pavlinovich]

When restoring a block the threaded holes for the studs were eaten away. It was a bit beyond my skills so I took it to a 
friend machinist who drilled them out with the same size bit but "oversize" then tapped them with the same size tap (yep 
you guessed it "oversize") then made me new studs on his lathe with one end to suit the threaded holes and the other end 
to suit the nuts (which were still in good nick) from the original wasted studs.

Want me to ask him if that is the real use for "oversize" or if they were just convenient and have some other purpose?

The only other possibility I can think of is tapping a mould for a casting since castings shrink - but I cannot for the 
life of me think of why you would do that because the threads would be rough and unusable in the final casting.

Regards
Paul

Dave Rotigel wrote:
> Hi Arnie,
>         I just looked at the taps carefully and all of them (except the 
> 1/2" X 12--which is marked GTD and not Wiley & Russell) have 1/32 
> stamped on them as well. I just measured the Wiley and Russell taps ( 
> 3/4', 5/8", and 7/16") and found them to be between .025" and .031' 
> OVERSIZE. 1/32" equates to .03125". That would seem to mean that the 
> whole set (dies and taps) are 1/32 oversize.
>         The question would now seem to be "Why would anyone want a set 
> that is 1/32 oversize?"
>                 Dave
<SNIP>
-- 

pjp at steamengine.com.au
Emerald, Victoria, Australia
www.steamengine.com.au