What Type Is This Collet, Please?

This topic has 11 replies, 8 voices, and was last updated 1 December 2025 at 18:42 by Nigel Graham 2.

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30 November 2025 at 21:47 #827036
Nigel Graham 2
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@nigelgraham2
Among my magpie boxes are two of these, marked only by their cutter diameters: 10 and 12mm.

I have searched among Clarkson Autolock but did not find this pattern so I suspect another make. (I have an ‘S’ type collet set, I learnt.)

I made this rather unrefined sketch as clearer than I could photograph it, but as a guide, overall length 1-3/4″, body diameter 5/8″, and show the 10mm cutter size.

BTW They are surplus to me, so…..
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30 November 2025 at 22:24 #827043
blowlamp
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@blowlamp
I think it’s an Osborne milling chuck collet.

Martin.
30 November 2025 at 22:26 #827044
Bazyle
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@bazyle
Posilock?
30 November 2025 at 22:50 #827048
Andrew Crow
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@andrewcrow91475
I do remember using some collets like these about 45 years ago, it may have been an Ericsson chuck.

The only thing I do remember is that the collets were not very springy and they gradually collapsed so that it became very difficult to fit or remove the cutters.

Andy
30 November 2025 at 23:19 #827049
John Haine
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@johnhaine32865
Posilok?
1 December 2025 at 08:55 #827078
Tony Pratt 1
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@tonypratt1
Google ‘Posilock milling collets’ and all will be revealed.

Tony
1 December 2025 at 11:07 #827117
peak4
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@peak4
On 30 November 2025 at 22:24 blowlamp Said:

I think it’s an Osborne milling chuck collet.

Martin.

Just been out to measure my Titanic 2; they’re 0.881″ diameter.

Bill
1 December 2025 at 11:41 #827121
Nigel Graham 2
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@nigelgraham2
Thankyou!

Bill –

Yes -I’d meant 7/8, but had measured it by Vernier in poor light, didn’t account for those extra thous… and then mis-quoted it! The drawing’s correct (I think). Correct enough for identifying.

Right. So I can’t use them anyway… If anyone can.
1 December 2025 at 12:20 #827129
blowlamp
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@blowlamp
Bill and Nigel.

It seems that Osborn and Posilock collets are the same thing.

Thanks for the verifications.

Martin.
1 December 2025 at 14:26 #827161
Bazyle
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@bazyle
Posilicks were /are? sold by the likes of Warco for their import mills since maybe 30 years ago so thousands out there. Of course mostly with a set of collets but maybe someone who only got imperial collets would appreciate a metric one.
1 December 2025 at 18:12 #827185
old mart
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@oldmart
Definitely Osborn, my Titanic II uses them and I bought some new Posilock metric collets to complete the set, which fit exactly, they are still available as are the Posilock arbors. Same general way of working with threaded shank endmills as Clarkson Autolock, but not interchangable. Mine go up to 5/8″ and 16mm, I’m not sure if they have a larger range like Clarkson does.
1 December 2025 at 18:42 #827188
Nigel Graham 2
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@nigelgraham2
Thank you everyone!

I’ll see if anyone in my club would like them, but I do want them adopted as I use an ‘Autolock’ chuck.
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