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

[R & M Ingold]

Ive been thinking on this and it crosses my mind that patterns are made 
oversize to allow for shrinkage. Could these be made for pattern makers? 
Just a thought.
Reg & Marg Ingold.
Newcastle, NSW, Australia.
randmingold at hotkey.net.au
http://www.oldengine.org/members/randmingold

----- Original Message ----- 
From: "Dave Rotigel" <rotigel at alltel.net>
To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
Sent: Thursday, March 16, 2006 2:51 PM
Subject: Re: [SEL] Tap & Die Set Help Needed--OT


> Hi John, ALL the taps and ALL the dies in the set that I bought (except 
> for the 1/2 X 12) are 1/32 OVERSIZED!
>         Dave
>
> At 07:43 PM 3/15/2006, you wrote:
>>A little late chiming in but here are my thoughts.
>>Are both oversize or is one over and the other under. My thought is 
>>someone was trying to make patterns/castings already threaded and possibly 
>>hoping to just clean the parts up with an on size tool after casting. I 
>>also thought if the tap is undersize and the die is oversize then maybe 
>>they were used for roughing with standard taps and dies used for 
>>finishing?
>>
>>For what it is worth, all taps are oversize, at least real ones not made 
>>in China. They are designated with an H limit.  An H3 tap is .0015 
>>oversize, an H6 is .003 oversize--for every number the H value increases, 
>>the tap increases .0005 in size.
>>
>>Can't say I ever heard of an oversize die other than adjustable dies.
>>
>>Oversized taps, as was stated earlier, are used often where shrinkage from 
>>heat treat, hard-coat anodize, or nickel plating comes into play. But we 
>>are normally talking just a few thousandths--not 31.
>>
>>Someone also mentioned 12 pitch threads and yes they are still widely used 
>>on hydraulic cylinders.
>>
>>John Hall
>>
>>
>>
>>
>>----- Original Message ----- From: "Dave Rotigel" <rotigel at alltel.net>
>>To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
>>Sent: Sunday, March 12, 2006 1:13 PM
>>Subject: [SEL] Tap & Die Set Help Needed--OT
>>
>>
>>>Hi All,
>>>While at the Zolfo Show a week or so ago I picked up a nice old tap and 
>>>die set made by Wiley & Russell (Greenfield, Mass.) (It's got to be 
>>>rather old because the 1/2 " die indicated 12 threads per inch!) The set 
>>>goes from 1/4" to 3/4" and each die (while removable) has it's own 
>>>handle! The set is in a nice old wooden box measuring  37 1/4" X 10 3/4" 
>>>X 3".
>>>Now my question. Each die has 1/32 stamped (or perhaps engraved) into it. 
>>>What does this 1/32 stand for/mean? Any help on this will be appreciated!
>>>Dave
>>>
>>
>>
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