40 tpi puzzle

I bought what I thought were taper and bottom 3/16 ME taps and die recently. Got them out today and the die has BSW 3/16x40 on it. Is there
such a thing as 40tpi BSW? The pitch looks coarse and a piece of brass threaded with the die wont enter a hole cut with the taper. First time I've used ME, is it me?
Ken.
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ME threads are, technically, whitworth form. This refers to the thread form (angle, etc). The standard whitworth threads have differing pitches depending on size, wheras the ME series have a constant pitch.
A taper tap only cuts a full thread form at the very end of the tap (the big end). It is intended to be used as a starter tap, followed by second and bottom taps. After tapping with a taper tap you must then use the next tap to run through the hole. If you only use the taper tap a threaded rod will only just eter the hole before binding up, if it enters at all.
Regards
Kevin

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On Thu, 31 Mar 2005 23:41:43 +0100, Ken Parkes

There is a 40tpi Whitworth thread, but it is a 1/8".
Both Whit and ME thread tables are on our site:-
http://www.oldengine.org/members/diesel/Tables/whit1.htm http://www.oldengine.org/members/diesel/Tables/me1.htm
Have a look at the Small Whitworth table also:
http://www.oldengine.org/members/diesel/Tables/whit2.htm
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk http://www.prepair.co.uk
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