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Soft jaws

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steamdave29/07/2022 09:57:47
521 forum posts
45 photos

Somewhere, sometime ago there was a description of how to make soft jaws for a 3 jaw chuck. The method used hex aluminium with holes bored through the centre to fit over each jaw projection and secured somehow to the jaws.

Does anyone remember the design and where I would be able to find it? A Google search doesn't bring up anything for me.

I have seen Harold Hall's design, but I don't want to drill the jaws of my Pratt Burnerd chuck.

The Emerald Isle

Clive Brown 129/07/2022 10:06:14
862 forum posts
47 photos

Not quite answering your question but I recently bought soft-jaws for a 5" PB 3-jaw chuck from Rotagrip. Quick delivery and cost abour £30 including postage.

steamdave29/07/2022 10:07:31
521 forum posts
45 photos

That's £30 too much for me Clive!

The Emerald Isle

Thor 🇳🇴29/07/2022 11:06:38
1656 forum posts
46 photos

There is one solution at Mike's workshop, that may be of help. Another here.


Edited By Thor 🇳🇴 on 29/07/2022 11:08:38

JasonB29/07/2022 11:50:20
23022 forum posts
2763 photos
1 articles

Just drill and tap a hole in from 3 corners of the hex stock so you can put a clamping screw in that bears on the back of the jaw., the three remaining corners are what you use to grip the work

DC31k29/07/2022 14:34:45
725 forum posts
2 photos

There is another version here: and that references MEW 224.

mike robinson 229/07/2022 16:47:32
30 forum posts
15 photos

here you go


steamdave29/07/2022 16:54:39
521 forum posts
45 photos
Posted by DC31k on 29/07/2022 14:34:45:

There is another version here: and that references MEW 224.

That's it DC. Many thanks.

Also, your idea Mike was one I had seen before but had forgotten about.

Now to put some redundant ali hex to good use.

The Emerald Isle

old mart29/07/2022 20:56:28
3886 forum posts
264 photos

I have bought several job lots of used soft jaws on ebay very cheaply. You have to take a risk that they fit, as the descriptions do vary from concise to totally pathetic. Some have had only 1/4 machined away and some are 90% gone. The most worn are candidates for milling your own brand of slot and tenon for tops to be attached by SHCS. I have made some steel, some aluminium and a rotatable brass set made out of a section of hexagonal bar.

Making the complete jaws is possible with a rotary table on the mill, but I don't have the patience.

Buffer31/07/2022 15:23:09
343 forum posts
155 photos

Here's how I make my jaws last.



old mart31/07/2022 20:49:31
3886 forum posts
264 photos

Good idea, Buffer, and there is room at the other end of those jaws for another three for outside use.

JohnF31/07/2022 22:35:24
1172 forum posts
193 photos

I seem to recall that many years ago Myford Nottingham sold a modified set of soft jaws that used a similar idea to Buffer's system above but they used Hex bar for the inserts and the recess in the jaw was machined to accommodate the Hexagon. Depending on what was being machined etc this gave up to 6 stations on each set.

Always thought it was a great idea !


ega31/07/2022 23:24:11
2565 forum posts
203 photos

Here is Myford's rather unsatisfactory leaflet:myfordhsj2.jpg

old mart01/08/2022 18:57:00
3886 forum posts
264 photos

That Myford picture by ega is exactly the design that I used for the brass jaws I described in an earlier post, made simply because I had a bit of hexagon brass stock laying about. The have not found a job yet.

Neil Lickfold02/08/2022 08:31:59
890 forum posts
195 photos

Softjaws are great for one off jobs, but I find that when it comes for the repeat of that job, having to recut is a pain compared to just loading the previous setup. At home, I would rather make a sleeve with a step in it etc to hold the part. Mitybite do a range of inserts for softjaw solutions. One that I did at work was a piece of angle and screwed to the jaw with the hole very slightly offset for the countersunk screw. The inserts can be replaced and then the previous parts are run again. For worn chucks, having a support piece in the back to help the jaws pivot and then clamp down on the front is very useful. The back support will vary with each worn chuck. Some might only need a piece about 0.05mm or 2 thou smaller than the short part being held, while others might work better with a piece the size of the work piece as a support.

robjon4402/08/2022 10:58:37
154 forum posts

Hi all, I would go with ega's drawing above, on the rare occasions I have needed small bored soft jaws I have 2 sets lovingly hand crafted from nuts with 1" diameter threads, one with the corners inward & one with the flats inward, grip a small piece of hex bar, then skim the o/d to clean up, dot punch, remove, drill & tap for securing (cap screws) & Bobs your uncle or lazy person (your choice), tie up on piece of string & hang up in plain sight ready for the time they are required again & yes I know its a little crude we are not making fings for Mr Rolls & Mr Royce but in a previous lifetime I have done.


Roderick Jenkins02/08/2022 12:03:36
2201 forum posts
616 photos
Posted by ega on 31/07/2022 23:24:11:

Here is Myford's rather unsatisfactory leaflet:myfordhsj2.jpg

I suspect the Myford soft jaws were bought in from:

hex soft jaws.jpg

soft jaws 2.jpg


ega02/08/2022 12:21:26
2565 forum posts
203 photos



I don't suppose you have the "feature article on page 82"?

Roderick Jenkins02/08/2022 14:13:09
2201 forum posts
616 photos

Here you are:

hex soft jaws article.jpg

ega03/08/2022 09:45:31
2565 forum posts
203 photos


Many thanks for this interesting article by the late Stan Bray.

The precise construction is not clear, to me at least, from the Myford leaflet but I suppose that the jaws are located on some form of register and, of course, retained by the screws seen in SB's photo.

In my case, I bought a set of soft jaws and machined locating recesses in them for replaceable slave jaws.

If the slave jaws are merely trued with a reamer without stabilising them in some way the result might be unsatisfactory.

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