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clarkson autolock 3mt

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chris mcnicoll05/04/2020 16:08:16
42 forum posts
15 photos

afternoon all, i have a clarkson autolock with 3mt that i use on my Elliott Omnimill, its the smaller model but i could do been able to use some bigger cutters etc, ive seen a few used ones on ebay etc but all have the wrong arbour, is there any other way of being able to use biggers cutters? can you get an adaptor that goes from 3mt to 40int ??



Mike Poole05/04/2020 16:32:17
3162 forum posts
72 photos

It may be that the large Clarkson chuck which will take 1 1/4” or 32mm collets is not made with a 3MT shank. ER40 will take a shank up to 26mm and is available with 3MT. If you don’t mind changing chucks then you could just buy the collets for the cutters you wish to use, if you wish you could get the full range of collets from 3mm and retire the Clarkson, with care the screwed shank cutters can be used in an ER collet. You will need to change chucks even if you track down a large Clarkson as the large chuck won’t take the small cutters.


Phil Whitley05/04/2020 16:40:17
1394 forum posts
147 photos

the answer is probably!, I have a few R8 milling arbors, and found that Arc did an R8 to int 30 adapter which means I can use them on my Harrison H Mill. Infortunately they are closed at the moment, but their catalogue is still online, have a look,

also check Gloster tooling and the other usual suspects! RDG etc!

Phil Whitley05/04/2020 16:50:22
1394 forum posts
147 photos

Actually I think Mike is right, it looks like you can only go the other way, plenty of int40 to mt3 but cant find any t'other way round. it would be a big lump of a ting when you think about it!


old mart05/04/2020 17:02:48
3510 forum posts
216 photos

I would keep looking on ebay, just search for Clarkson autolock every time you are on the site, sooner or later you could be lucky. MT3 to er32 or 40 would be easier to find, I recon.

thaiguzzi05/04/2020 17:02:50
704 forum posts
131 photos

Yes external 40int, internal 3 MT adaptors.

I have a 30int external to 2 MT internal adaptor for the M1.

DC31k05/04/2020 17:26:36
586 forum posts
1 photos

I have always been under the impression that Clarkson made Autolock chucks in three sizes, small, medium and large.

I cannot remember the size range but someone might have a Clarkson brochure somewhere.

You should be able to find a medium in 3MT, but are unlikely to find a large. The medium ones are quite rare.

If you do find one, check it for runout as the medium ones can be too much cutter for the size of the shank. I had an R8 medium one that had suffered this. I gave it someone and he did manage to straighten it.

Emgee05/04/2020 17:37:15
2312 forum posts
277 photos

Yes, Clarkson did make a very small Autolock with approx 1" diameter body and max cutter size of 1/4".


Edited By Emgee on 05/04/2020 17:38:56

DC31k05/04/2020 19:52:05
586 forum posts
1 photos

OK, found the literature.


Both documents well worth downloading.

Maximum size of cutter for large chuck depends on gauge line of taper - too small and you only get 1" or 25mm.

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