Soft jaws for Clausing 5914 lathe?

I'd like to get some soft jaws for the 3-jaw chuck on the Clausing 5914 lathe. This appears to be the chuck that came with the lathe. The jaws
are two-piece, and can be removed and installed the other way.
The chuck body is marked "BP71/6206", and is 8" in diameter.
Apparently these jaws are the "American standard tongue-and-groove" type. The lengthwise groove is 0.31" wide, the crosswise tongue is 0.501 wide, and the centers of the screw holes are 1.75" apart.
There seem to be a lot of people making chuck jaws, none of whichg I know anything about.
What sources/makes are good, are bad, and why?
Thanks,
Joe Gwinn
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They're easy to make if you have a mill, Joe. I've never purchased soft jaws in my life! The best choice is mild steel, so the jaw can be rebuilt by adding new metal after they're served a long and useful life. I have also used both 7075-T6 and 6061-T6 aluminum.
Harold
Harold
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I'm assuming you mean welding them up. I got to mention that to our engineers. I have a feeling we just make new ones.
Wes
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wrote:

And you probably have a program for the jaws stored.
JC
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wrote:

Yes, by welding, Wes. I've done that on many occasions. The only concern is getting them similar in weight and orientation so they remain balanced. I'm still using one set of jaws that started life in my shop in 1967!
Harold
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I see that they would be easy to make, but first I want to know the price if purchased, to be sure making them myself is worth the trouble.
Joe Gwinn
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    No way for me to tell what fits that lathe. I'm using a Bison 6-1/4" chuck with two-piece jaws.

    [ ... ]

    IIRC, the price for a set of soft jaws for my Bison was about $60.00. I would say that it is worth while making your own. :-)
    You might dig through the MSC catalog to see what they charge for sets to fit your measurements.
    Enjoy,         DoN.
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A datapoint.
And I do have a mill, which has been feeling neglected since the Clausing 5914 lathe arrived and was so in need of doctoring to cure its severe case of the chatters.

That's what I'll do. The general lack of opinions on the matter tells me that soft jaws are a commodity. It's not like they have to be made by watchmakers and hand-polished by virgins. On the other hand, hard jaws ....
Joe Gwinn
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I ended up buying a set (MSC # 01933480), and they fit tightly and work very well.
I did number the soft jaws 1..2..3 so I'll put them back on the chuck always the same way.
I recall you warming about the danger of getting clipped by the spinning big jaws. This is a real danger. I didn't get clipped, but there was a close call. That would have HURT. I may make a guard cover.
I would guess that pie jaws are safer.
Joe Gwinn
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On Fri, 13 Feb 2009 15:05:21 -0500, Joseph Gwinn

Most folks make them to suit out of mild steel or aluminum.
--
Ned Simmons

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Joseph Gwinn wrote:

I just made a set out of 6061 Al at school on Thur. Havent used them yet but need them to hold some threads without "buggering" them up. Havent figured out how to hold the jaws in compression while threading all the way through the soft jaws yet. ...lew...
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In such a case, I like the jaws to project inward, beyond the surface of the master jaw. Grip your spider (or piece of stock) on the master jaw, allowing full access to the soft jaw. Works fine, Lew.
The isn't usually need to grip by the thread itself. You won't harm the threads if you grip on the major diameter. Only problem with that is if the thread is drunken, you may not achieve the alignment you hope for. That's the beauty of soft jaws. If you machine them to conform to the target diameter, they grip without damage.
Harold
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...

...
I had a project where I had to make four inch high jaws and the part had to fit down inside the chuck (NMTB tool holder). So I drilled and tapped 1/4 20 holes in the top of the jaws. Then a plate to bolt on. I liked this method so well that i made a special plate to fit all sizes with spiral slots and now I always bore my jaws this way.
Karl
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Karl Townsend wrote:

Karl I don't see that in my head. Can you post a pix somewhere of that? I want to hold a long piece of all-thread and work the end / cut off thread out and repeat so there is no place to put a support to clamp on. I'm thinking three small pieces sort of between the corners of the jaws. Harold, I'm not sure exactly what your describing but "maybe" a sacrificial piece that the the master jaws clamp on before the soft ones touch that I can then drill through and tap then remove???? Yes?? Thanks. ...lew...
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On Sat, 14 Feb 2009 07:16:27 -0700, Lew Hartswick
<snip>

<snip> -------- You may be working too hard here, depending on the thread size, work piece length, TIR required, etc.
Easy way is to get 3 nuts to fit the threaded piece. Thread 1 nut, a washer and two more nuts on. Space the last two nuts so they clamp at the front/back of the 3 jaw chuck, with the front projecting very slightly in front of the jaws. Run the nut on the other side of the washer down against this nut and torque to suit to prevent the part from turning. If runout is excessive try different nuts or shims between jaws and nuts. Not suitable for production, but fine for a typical hobby shop one-off.
As a safety tip, if you are machining threaded bar like Allthread and it extends through the headstock and out the back, be very careful of "whip" that will likely develop. In this case you will more than likely have to cumshaw up some sort of bar support from a piece of pipe and some stands to restrain the part that is sticking out if it is more than a few inches, depending on the workpiece diameter. You may also find it helpful if this is thin stock to make some sort of bushing to restrain the stock inside the spindle and keep it centered.
Good luck and let the group know how you make out.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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    [ ... ]

    I just use the appropriate size of 5C collet for that kind of work.
    But if you don't have the collets, take a cylinder of brass or mild steel (hot rolled, not cold to avoid the stresses in the material), drill and bore to be a sliding fit on the allthread, then use the mill and a slitting saw to cut a radial slit from the OD to the ID. Put this in the chuck (with the slit facing away from the #1 jaw, if you want repeatability) and when you clamp the jaws on the cylinder, it will close on the allthread and grip it strongly.
    If you really insist on threads, thread the cylinder before slitting instead of boring to fit.
    Good Luck,         DoN.
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On 14 Feb 2009 20:36:48 GMT, "DoN. Nichols"
<snip>

<snip> If the TIR required is not too close or you can spend some time shimming, it is possible to use two nuts that fit the Allthread. Hacksaw a slot though through the middle of a flat on each nut. File the burrs out of the slot with a triangle file [simply file straight down below the root of the thread], and as required clean out with a tap to a easy running fit on the Allthread. To use, thread on the rod so that one nut is to the front of the chuck jaws and one nut to the back, and position the nuts so the slots are between two jaws. When you tighten the chuck the nuts will squeeze down and grip the rod. As before watch out for whip of any material extending out the back of the headstock.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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Yeah, that's it Lew. I don't recommend drilling and tapping, however. You'll have less than good fortune accomplishing your mission because of the interrupted cut. If it's possible, bore the hole for a round and straight result. The exception might be if you can get the jaws all but touching.
Do consider holding the material by the major diameter instead of threading the jaws, too. Unless your application is critical of concentricity, p.d. with the work you'll do, it's a lot of trouble to go to for little, if any, gain. You'll be duly pleased with gripping the major under all but the most trying of circumstances.
Long ago I did a series on soft jaws and how to apply them. In one of the articles I talk about a spider, which is used to bore soft jaws. It avoids the hunt for a specific size of material for each time you need to machine the jaws, with the added benefit of being able to true the jaws by removing only a few thou, even when the profile may not be perfect for the application. It need not be, not as long as you can achieve a respectable surface area.
Regards the spider, if you're interested, they're real easy to make. Using a fairly large nut (1" or so) , drill and tap at 120 degree intervals for a socket head cap screw. Mine are 5/16-18, for use in an 8" three jaw. Locate the three tapped holes near the edge of the nut, so you can get the spider as far back in the jaws as is possible for machining the jaws. You can even locate on the master jaw, allowing for through boring.
If you're interested in reviewing the posts, I'll provide links. Lots of good reading, with pics to help in the descriptions.
Harold
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I'd be interested too. Perhaps it would be good to collect the posts into a tract that resides in the dropbox.
Joe Gwinn
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wrote:

snip-
Here's the link. http://www.chaski.org/homemachinist/viewtopic.php?tB66
Unless you are a registered reader of the Chaski board, pictures can't be viewed. Otherwise, you should be able to read all of the posts on the rather long thread.
Because the posts were done long ago, when the board was running different software than is currently used, some of the pictures are no longer there. Those that are important are, however.
Hope you find the posts useful.
Harold
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