1/2" UNC die chasers

My list says I have 2 sets for a 1/2" head, I'll physically check tomorrow whether that means two *good* sets, ifso I can sort you out with one.

The list also says I've got some more 1/2" 13tpi, they're not listed as UNC so they should be Whit form. Was that ever a 'standard' thread?

Cheers Tim

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Andrew.

Did you get fixed up ? I have sets for 1/2", 3/4" & 1" head. I am never going to use all of them in my life time, so can spare set.

Phil (Harrogate

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Charles

Andrew That's not quite answering the question.

Herbert type die chasers which aren't marked otherwise are assumed to be of Whitworth form. As a result of buying some job lots of chasers I have ended up with some fairly unusual 'special' combinations of diameter & pitch, and there's no reason why 1/2" x 13 Whit form couldn't be one of them. In fact I now can't find those chasers, they may well have been a fictional result of a tryping error, but I do have others which are just as unusual. ISTR reading somwhere that 1/2" x 12 has at one time been an AN or similar (60 deg) standard, though I may remember that wrongly. I just wondered whether 1/2" x 13 Whit form was ever used as anything more than a 'special'.

Cheers Tim

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