View Full Version : which steel for small jeweller roller?

3rd Nov 2017, 05:09 PM
hello, i need to make a couple of these rollers for use with gold and silver. i am not sure which steel would be best, my fitter friend said to use a mild steel and then case harden the edge, i am just worried any heat treatment may distort it as there is a keyway, should i go with that option or use a medium carbon steel without any heat treatment? this would be done on a lathe. cheers for any advice.https://uploads.tapatalk-cdn.com/20171103/4fe849ccfb5bdea2ef1be930bbf27283.jpg

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11th Nov 2017, 04:21 PM
I would make it simple and use an air hardening low distortion steel like Bohler K110 ( D2 tool steel ) . If you have a reasonable size lathe it will machine with HSS and carbide inserts BUT you must keep it cool or it hardens up automatically . Once machining is done you just heat it up red hot for a few seconds and it hardens up .
If you can't keep the job cool for what ever reason then EN36A is soft to turn steel that will not harden quickly due to very low carbon content and is very suitable to case hardening .
I see you have to broach a keyway slot so a lot depends on how much broaching power you have. If you will have difficulty cutting the keyway then use EN36A and case harden it after all machining and polishing is done . It's not that big so broaching the keyway should be ok in most unhardened tool steels . Repolish the roll surface after hardening .
You could also use an oil hardening tool steel like 01 because minor heat treating distorsion should not affect such a part adversely , correct me if I'm wrong . As one roller would be adjustable I would think .
A key can always be polished down a bit to tap in neatly if it's a bit tight after heat treatment . If it expands and the key is loose then make a new one . Small part like that distortion should be minimal .
For a drive fit on a 1.25 inch ( 31.75mm ) shaft diameter make the hole smaller than the shaft by .000825 inch. ( .020955 mm ) .

12th Nov 2017, 12:44 AM
What type of mill is it for you can most likely by it a s a spare