Drawing a blank on these…………………..

This topic has 8 replies, 7 voices, and was last updated 11 June 2016 at 12:34 by Michael Gilligan.

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10 June 2016 at 14:51 #18118
Rik Shaw
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@rikshaw
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10 June 2016 at 14:51 #242220
Rik Shaw
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@rikshaw
I have a number of these – all new. They are marked "Clarkson – Blank". There are small coned centres at both ends and I have sizes 3/8" and 1/2" diameter. I have googled but find no reference to them. Does anyone know what they were produced for as I have drawn a blank. All I can think of is that they could be ground as form tools or D bits.

Rik
10 June 2016 at 16:23 #242232
Rainbows
Participant
@rainbows
If they have a centre hole at each end that would make it easier to mount them on a grinder to make the final tool. Form tool making sounds about right.

Also if you didn't know those threaded shanks fit into Clarkson Autlock collets.
10 June 2016 at 18:43 #242254
Tim Stevens
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@timstevens64731
Potential counterbores?

Tim
10 June 2016 at 22:30 #242274
Johnboy25
Participant
@johnboy25
I agree with Tim – they look like they can be ground into special size counterbores. I remember I found an odd size years ago – I had the tool room grind the pilot to a useful size. I've still got it in the arsenal.

John
11 June 2016 at 08:50 #242298
Rik Shaw
Participant
@rikshaw
The counterbore idea is interesting and yes, it would work. However, in a production grinding environment it is/was common practice to leave a small centred "nipple" exactly like this for between centres grinding. It makes it easier to slice it of with an elastic cutting wheel after the necessary centre grinding has been completed.

Rik
11 June 2016 at 09:22 #242301
Neil Wyatt
Moderator
@neilwyatt
Surely they don't have a specific purpose – if they did, what would be the point? They are for you to grind into whatever special shape you need – a tapered endmill, a stepped cutter, a bullnose or concave shape….

Neil
11 June 2016 at 10:47 #242312
Andy Ash
Participant
@andyash24902
It occurs to me that these could be used to check run-out at a realistic distance from a milling chuck.

Obviously you could just do that with a bit of ground stock, but these have the advantage that they have ground threads, and would be correctly mounted in a Clarkson autolock collet chuck.

Obviously you could clock a cutter near the chuck, but you would not be able to clock it at the tip where it matters. With a blank, those problems vanish.
11 June 2016 at 12:34 #242327
Michael Gilligan
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@michaelgilligan61133
Posted by Neil Wyatt on 11/06/2016 09:22:37:

Surely they don't have a specific purpose – if they did, what would be the point? They are for you to grind into whatever special shape you need …

.

Quite so, Neil

… Comparable to 'blank collets' [except for being the opposite gender]

MichaelG.
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