Split dies

I have several threading dies that I inherited that are not split but shoul d be. The 'new old stock' un-split die I've just started using is a 1/4" BS
F but I do have other sizes. I t works OK, but being able to adjust it coul d be useful.
They are 'normal' HSS round dies with dimples on the circumference where th e die-holder adjusting screws fit and vee slots where they should have been split for the spreading screw.
I have an instruction from the manufacturer stating that the die should be split before use. No instructions were given on how to actually split the d ie and I'm reluctant to give it a whack with a cold chisel or similar. Othe r split dies I own have obviously been split after manufacture.
Although I could split the die with a Dremel or similar, I would like to kn ow how it was done properly.
Does anybody know how this was done?
Thanks in advance.
John H
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Not with a cold chisel :-)
Cutting HSS isn't easy, as I am sure you know, and a solid chunk like a die would probably challenge a Dremel. I've drilled hardened steel using a tungsten drill but it took some doing. Given the choice, I would aneal, machine, harden, temper something previously hardened etc. However, that probably isn't practical for you die.
Are you sure it is intended to be split and it isn't a 'repair' die which, I believe, are not split. They have the dimples but they stop the die turning in the holder.
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On 11/11/2015 9:23 AM, Brian Reay wrote:

Slim cutting disk in a 4"angle grinder would do it for me .
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