Diestock holder for 42mm diameter dies

[Andrew TinsleyParticipant @andrewtinsley63637]

I have a couple of dies which have a diameter of 42mm. This is not a standard  diameter for metric dies as far as I can determine. 1 5/8″ is a standard imperial size for dies, but it is somewhat less in diameter than 42 mm.

Do I assume that my dies are 1 5/8″ despite them being 42 mm diameter and not 41.275 mm as 1 5/8″ would suggest?. I can easily make a 42mm diestock if necessary, and would probably cost somewhat less to make than a second hand 1 5/8″ item.

Really just curious as one of the dies is imperial and the other metric. I suspect that I am splitting hairs and a 1 5/8″ diestock would be more than adequate.

Andrew.

[Andrew Tinsley]

On 19 May 2026 at 12:53 Andrew Tinsley Said:

This is not a standard  diameter for metric dies as far as I can determine

FWIW, the dimensions of ISO metric (and imperial) dies are here (ISO2568):

https://cdn.standards.iteh.ai/samples/7527/671f054ac2104eedb76af5d5cdd7f98c/ISO-2568-1988.pdf

You could see if there is a US standard for the same (I looked in the ANSI B94 series, which has one for taps, but not dies), which would confirm that 1 5/8″ is an ‘official’ figure. There might be an old BS that also covers the items.

The ISO above lists 45mm as a standard – a 1.5mm shim would make a 42mm die fit the larger holder.

See also:

https://tameson.co.uk/pages/tap-die-standards

[Andrew TinsleyParticipant @andrewtinsley63637]

Thank you DC31K, for confirming that a 42mm is non standard diestock size, my information says that the standard size jump from 38mm to 45mm.

So it appears that my 42mm diameter dies are intended for a standard imperial 1 5/8″ dieholder, despite the slight difference in diameter.

Thanks,

Andrew.

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