WF thread..

I found an old tap and die with just "WF" written on it, along side the TPi and dia.

What does it mean?

Thanks

Michael W

Firm or owner's initials ?

Emgee

Whitworth Form

   whitworth fred       if it come from London !

I've got a 2" square die with R stamped on it ... A 99 year old guy , who if still alive would be 110 gave it to me

Said it was his fathers who worked on the railways... Railway thread ?

Edited By Hacksaw on 07/01/2017 14:40:31

I have a number of taps and dies with WF on them and it stands for Whitworth Fine.

Brian

Thanks, I tried searching for it but nothing came up.

Hopefully my forum thread title will  come up as a close result on a search engine to help others as well.

Michael W

Edited By Michael-w on 07/01/2017 15:52:14

It's definitely Whitworth Form.

I have some taps here 2" x 4.5 tpi, clearly marked WF and no way is 4.5 tpi classed as fine thread.

2" x 4.5 is BSW, 2 x 7 is BSF, so WF Whiworth Form is my vote.

Ian S C

Perhaps the OP might have listed the diameter and pitch at the beginning? Much less obscure discussion and more sensible outcome in fewer guesses (or without any) from the members. I expect JS is correct.

It's 1/8 x 32tpi I think.. I was satisfied with JS's answer from the start. Whitworth form, makes complete sense. Thanks for the help.

The term Whitworth form suggests that there was another thread form in general use at the time or earlier.

JA

1/8" whit is usually 40tpi, so may not be a Whit thread but a 55degree thread so could be 1/8 x 32 ME.

That sounds like I got a lucky find, so does ME have a common form with whitworth?

Michael W

Why make life difficult when with a bit of extra effort you can make it abso bl***y lutely impossible.

Regards Ian.

 WhitworF

Edited By Circlip on 08/01/2017 14:31:36

Oh but there was.

Every engineering concern had their own, even to the extent that one nut would only fit one bolt.

Whitworth was the first to standardise the thread system and so anything marked WF denoted it was to a standard.

The model engineers thread was BSEF/extra fine, there is a parallel to this in USA, the UNEF.

Ian S C

Edited By Rick Kirkland 1 on 09/01/2017 10:48:46

.

Yes ... or, to put it more correctly: the ME threads are 'Whitworth Form'

MichaelG.