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Think you have trouble losing your chuck key?

Just a little project, to see if it was possible!

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William S31/03/2021 19:03:21
69 forum posts
307 photos

Hello all

Think you have trouble misplacing you full size chuck key? How would you contend with this size(I have misplaced it several times myself whilst making it!!)

Sorry about the orientation.

It’s a 1/3rd scale miniature 80mm 3 jaw chuck. It still needs finishing off, the pinions are my next stumbling block really. If there is interest I can explain how I made certain parts!

Thanks for reading


Dave Halford31/03/2021 19:17:38
1890 forum posts
22 photos

What chuck key?devil

David George 131/03/2021 19:27:18
1716 forum posts
500 photos

Here's my 4 jaw chuck not quite as hard as a self centering 3 jaw.20170907_114623.jpg



Hopper01/04/2021 12:43:55
5508 forum posts
137 photos

Goodness. That's rather wonderful. Are you making the lathe to go with the chuck? And yes please, how did you make the scroll? Lathe with extremely coarse cross feed? Or mill with table and dividing head geared together? Or CNC magick?

Brian Wood01/04/2021 12:59:53
2498 forum posts
39 photos

Hello William,

What a cracking piece of work. Please add me to the list of those who would like to know how you went about the tricky bits involved. It's a little sweetie.


Bo'sun01/04/2021 13:52:53
584 forum posts
2 photos

Amazing detail (and patience). Another vote for "how it was done".

On a similar theme, have you seen Joe Pieczynski's mini lathe project on You Tube?

Yes, the American drawl can be a bit tiring, but interesting none-the-less.

Craig Brown 201/04/2021 14:24:50
51 forum posts
14 photos

Very nice indeed, would also be interested in the finer details. I like how the jaws are to scale also because that is my problem with the ones made for the kits like David's, they are always too big (no disrespect David, your model looks great) but the makers (Stuart and others) must deem it too fiddly to do the jaws to scale?

Mike Poole01/04/2021 15:31:30
3167 forum posts
72 photos

That chuck looks a bit heavy for a Myforddevil


Nigel Bennett01/04/2021 16:21:49
436 forum posts
19 photos

I take it you're going to make it a working Griptru one as well...

It looks really good, William - and if you've got to do the pinions somehow! Keep us posted on how you did them...

Tom Sheppard01/04/2021 17:54:45
31 forum posts

Isn't that a full size 26 2/3mm chuck?

William S01/04/2021 23:25:49
69 forum posts
307 photos

Hello all

Thank you for the kind words, its just going to stay a standard chuck, as I am not an owner of an 80mm Griptru!

I have done one pinion, Its not right as I forgot about the involute detail when grinding the D bit!:5c8a4eca-da81-4041-9933-43a0ff1bdb25.jpeg

As can be sen here the middle D bit just has straight sides, I am yet to experiment with making a involute form D bit so watch this space. I am using a D bit as I don't think any other cutter would work. A fly cutter style tool or a commercial cutter as it has to clear the pin sticking out the front of the pinion.


That's the pinion before I cut the teeth,

Okay you asked for an explanation on the finer details so here goes:

The scroll and jaws have so far turned 2 of these 0.5mm slot drills




The scroll and jaws are machined on my Alexander 2c pantograph engraver using the full size original, and the pantograph ratio set to 3:1. I first roughed out the ends of the jaws using a 1mm endmill and a 3mm stylus, (the pantograph ratio x cutter dia = stylus dia) Then I moved on to the 0.5mm slot drill and a 1.5mm stylus to finish machine the profiles.

Getting set up here is the most difficult part one has to really be creative with an indicator!, I needed to get the "fence"(1,2,3 block) on the copy table in relation to the fixed jaw on the vice on the machine table. This was done by calculating the centre of the original jaws plus the radius of the stylus, turned out to be 4mm exactly. A slip gauge was used. Then holding the stylus against said "fence" and slip and sweeping an indicator either side of the 1/3rd scale jaw on the machine table to centralise it.




The 0.5mm slot drill is running at full lick of 20,000rpm, 0.1mm depth of cut set with the knee on the machine, about 30mins per jaw

The scroll was largely the same process, only I used the 0.5mm cutter to fully machine it, no roughing cuts. I removed the copy table and held the original scroll on a mount. Sorry no pictures of this stage! so you will just have to put up with my explanations. The scroll took about an hour and a half to machine.

The jaws were made out of a strip of gauge plate which I surface ground in my lunch break at work to fit the slot in the chuck body, the slots either side were cut using a little T slot cutter, in this set up, enables both sides to be at exactly the same depth etc.



The T slots in the chuck body were cut in this little fixture on the BCA ,slot first then using a miniature carbide "key seat" cutter (off ebay, Klot carbide, no links just an impressed customer). the fixture allowed easy lineing up with the pre drilled pinion holes that were drilled when it was still attached to the parent stock from turning the i.d. and o.d etc



The gears were cut on the Pantograph using the aforementioned D bit in this set up:


I hope that explains a bit!





Edited By William S on 01/04/2021 23:28:09

Craig Brown 202/04/2021 04:41:52
51 forum posts
14 photos

Impressive work. Inventive use of the pantograph too, I like it!

Dave Wootton02/04/2021 06:33:27
230 forum posts
56 photos

Inspirational and beautiful work William, I am in awe. Thank you for posting this and please keep them coming, this is just the sort of thing I love to see on the forum.


DiogenesII02/04/2021 08:44:58
432 forum posts
181 photos
Posted by Dave Wootton on 02/04/2021 06:33:27:

Inspirational and beautiful work William, I am in awe. Thank you for posting this and please keep them coming, this is just the sort of thing I love to see on the forum.


..Exactly my sentiments.. Thanks for posting Williiam

Michael Gilligan02/04/2021 09:06:10
19599 forum posts
997 photos

In another recent thread, I wrote:

... why is it so often presumed that one’s horizons will inevitably expand in terms of physical size ?

Doing smaller stuff better is another option.


I think you have validated that beautifully, William !


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