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.

Reply to
Ken Parkes
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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

Reply to
Kevin Steele

There is a 40tpi Whitworth thread, but it is a 1/8".

Both Whit and ME thread tables are on our site:-

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Have a look at the Small Whitworth table also:

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Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

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Reply to
Prepair Ltd

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