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Strange WW1 Chuck - 1MT

What is this chuck for - any ideas?

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John Paton 129/04/2020 11:08:40
312 forum posts
17 photos

estcott chuck enlarge.jpgestcott chuck side large.jpgIn amongst my pile of odd bits is this 1MT chuck, similar to a small version of the chuck on a Stanley wood drilling brace but much smaller capacity.

What i don't understand is shy it has a diamond shaped grip rather than square as I have seen no tooling with that shaped end.

Any ideas of what it was for?


estcott chuck side .jpg

Michael Gilligan29/04/2020 11:17:04
19324 forum posts
964 photos

Can’t see all the text in your pictures, John

... Is there a patent number included ?


Andrew Johnston29/04/2020 11:17:21
6325 forum posts
681 photos

It rings a vague bell, but I can't remember where I've seen one before. embarrassed A diamond shape doesn't preclude holding round objects like drills, and may have been a way round the patents for Jacobs style chucks.


Chris V29/04/2020 11:29:07
310 forum posts
42 photos

Hi John,

Strange but it appears its for holding normal ie round drill bits. Westcotts Little Giant Improved Chuck was available in varies sizes and is shown in the Drummond literiture I had from Tony at uk under drill chucks.

Aparently there was a Pratt Improved design as well that was very similar. 1MT would fit my lathe! (-:



John Paton 129/04/2020 11:30:52
312 forum posts
17 photos

Looking at the side rather than the end I now see that this is No 00 IMP V1

J.H.Westcott's Little Giant Patented march 17th 1874 and april 14th 1885 Made by Wescott Chuck Co Oneida N.Y.

Importe des Etates Unis D'Amerique

So mine was presumably an export to France or maybe French Canada?

Brian Sweeting29/04/2020 11:35:12
453 forum posts
1 photos

Maybe the patent gets close ....



Sorry I think this 1874 patent is closer..


Edited By Brian Sweeting on 29/04/2020 11:37:07

John Paton 129/04/2020 11:41:12
312 forum posts
17 photos

Never ceased to be amazed at you chaps knowledge and resources and so quick too! Top marks to Chris and Brian and thanks to Andrew also.

Many thanks


Clive Foster29/04/2020 11:57:52
2890 forum posts
104 photos

As the jaws are fully supported at all times this style may have persisted well into the Jacobs and similar style key chuck era as being considered to give better support and grip than the Jacobs type whose jaws inevitably project from the body when smaller sizes are held.

Mine is, I think, Crown brand as the only visible markings are a simple crown graphic.

Bit bigger than yours. Capacity is 1.1", seems odd for the era as 1 1/8" would have been possibly more logical. Almost 3 1/2" diameter by 3 3/4" long with a 6 tpi, 1 3/4" mounting thread in the body. The thread currently carries an obviously factory adapter with 3/4 Whitworth internal thread having a teensy 1/2" by 1" spigot screwed into the back. Which look, um, less than adequate!

I'm currently wondering if it can be adapted to use on my proposed bigger version of the Clarkson Drill sharpening accessory so I can do my large drills. It would certainly do nicely in a four facet system, which would be almost trivially easy to make.


AdrianR29/04/2020 12:38:15
542 forum posts
36 photos

I think there may be one of those kicking about in my dads old stuff, I am sure I saw one when I was a kid.

You can still buy them too **LINK**

Making one of those could make an interesting project too.


Phil P29/04/2020 12:46:58
790 forum posts
194 photos

I wonder if one of those would be any good for holding drills for sharpening on a T&C grinder with a bit of modification.

If the back end was made so a drill could pass right through and assuming those vee jaws would grip the drill flutes accurately ?

Just my 2p worth.


P.S. I have just read Clive's reply two posts up.

Edited By Phil P on 29/04/2020 12:48:42

old mart29/04/2020 13:21:18
3418 forum posts
210 photos

Funny that the patent illustration shows jaws with a square hole which is more logical.

Clive Foster29/04/2020 13:38:55
2890 forum posts
104 photos


Great minds and all that.

The issue with using that style of chuck on a drill sharpener accessory for a T&C grinder is body clearance from the grinding wheel.

My Clarkson system handles 1/8" to 3/4" with a 6 jaw chuck having jaws extending 1 1/2" beyond the chuck tapering to about 1/2" outside diameter fully closed. The Clarkson geometry requires 1/2" of drill projection beyond the tip of the chuck jaws to produce a standard 118° point. Chuck body to wheel clearance approaches 1".

Given the relatively large body diameter and zero jaw projection with the Wescott style two jaw chuck it seems that using it on a Clarkson style sharpener to produce a conical point on smaller drills is going to be impractical because the drill point projection beyond jaw support will need to be rather greater. Hence the drill needs to be strong enough to stand grinding loads at the greater projection. My feeling is that 3/8" diameter would be the absolute smallest for satisfactory results.

I see no intrinsic reason why a system couldn't be made with a standard Jacobs chuck with the back drilled out and a tube mount for small drills and a Wescott style for the bigger ones. What's important is the absolute position in space of the drill point relative to the pivots when being ground. Stick out is immaterial except for stability.

Similar body and jaw clearance issues with a four facet system. Obviously if you set things to grind using the lower face of the wheel there will be room for the main body to slip beneath the wheel rducing stick out issues. But it still looks to be a large drill solution.

The layout used by Kaindl to grind on the periphery of the wheel looks more promising **LINK** as that provides clearance for a large and apparently cumbersome toast rack style Vee holder. Which for practical purposes is a naked version of Wescott chuck innards. Would, of course, work fine with an ordinary bench grinder (once someone reverse engineers the geometry!).


Edited By Clive Foster on 29/04/2020 13:39:46

Edited By Clive Foster on 29/04/2020 13:41:16

JasonB29/04/2020 13:40:08
21652 forum posts
2495 photos
1 articles
Posted by Andrew Johnston on 29/04/2020 11:17:21:

It rings a vague bell, but I can't remember where I've seen one before. embarrassed

On this forum as someone asked with a similar chuck, several like it in my old 1895 tool catalogue for holding round bits.

This is the time, you can see the interlocking jaws with the "v" faces and this "improved" one also has drive dogs that fit the end of the bit to stop it slipping. There are also example swithout teh dog liek the OP has.

drill chuck.jpg

Edited By JasonB on 29/04/2020 13:46:19

Phil P29/04/2020 15:54:01
790 forum posts
194 photos


I already have a set up for doing Four Facet drills on my Union T&C grinder. I use DA collets on that rig up.



Maurice29/04/2020 16:59:16
469 forum posts
50 photos

I have one of these chucks. I bought it for a few pounds at a club auction many years ago. Mine was used by a firm called "Hills" and was used to make the adjusters for violin bows. These are hexagonal, a shape that these chuck seem to be made for.

Regards Maurice

John Paton 129/04/2020 17:09:04
312 forum posts
17 photos

Thats a point Maurice, this would hold hex stock rather well.

old mart29/04/2020 21:46:22
3418 forum posts
210 photos

That modern advert for the chuck had a clue in it. Did you notice it was intended for woodworking?

Nigel Graham 229/04/2020 23:57:12
1786 forum posts
22 photos

It looks as if this was once a common pattern.

Of my two specimens, typically I can only find one at the moment. It is apparently of " Crown " make - at least as stamped rather faintly on the body, together with a symbol like that for the King in chess notation.

More faint stampings give the 0 - 1/2 inch capacity.

It has no taper shank, but instead a though-hole that appears to be bored MT2 - an odd way round of doing things.

Testing the Vee-jaws shows they are for hexagonal, not square stock.

I have an idea the other, wherever it is hiding, is a Westcott chuck; and also has a taper (Jacob's??) socket rather than shank.

What tooling nowadays has a hexagonal rather than round or square shank? It's now very common, for screwdriver bits and the like. So maybe these rather splendid antiques have a new role, on pillar-tools!

JasonB30/04/2020 07:13:19
21652 forum posts
2495 photos
1 articles

120deg Vee would fit round just as easily as per my scan, the others in the same catalogue show them holding round shanked drills.

Clive Foster30/04/2020 08:51:31
2890 forum posts
104 photos

Likely 120° Vee was chosen as an easy way to get a more secure grip on the round drill shank than 90° Vee.

120° puts more of the holding force outwards into the slides and less into the screw than 90° which (theoretically) splits them equally hence generating more grip force for any given torque on the screw.

Plenty of grip would seem desirable if using the split parallel to morse taper converter sleeve shown in the catalogue page posted by JasonB above. Not something I'd be confident using, not even with the tang drive widget fitted.

NIgels' Crown chuck seems rather different to mine. MT2 bored through hole does indeed sound a strange way of making things. Unless its for a special purpose machine. The big internal thread on mine looks to be much more sensible.


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