"Adjust Tru" Chucks

Standard and optional items for the Sieg C2-style 7x-- minilathes usually include 3" 3-jaw chuck, 4" 4-jaw chuck, and 6"+ faceplate. See eg and . However, littlemachineshop.com lists a number of 5" chucks and adapters for Sieg C2-style minilathes, as at eg

Maybe he planned (before he got the mill) to use them for milling on his lathe. The 7x14 mini lathe has MT3 spindle taper and MT2 tailstock taper.

Reply to
James Waldby
Loading thread data ...

3" is the size of the chuck that came with my 7" x 14" lathe.(I wanted to turn 4-1/2" plates,which is why I settled on getting the 5" four jaw chuck, which I'd also use with the 6" rotary table I'm about to get for my mini mill/drill.

The ring only has threads at the I.D. and is knurled on the O.D. There are no slot, holes, etc. on the ring. It was definitely meant to be turned by hand.

Or, as you would put it, things would get pretty exciting. :-)

Ok. :-(

Before I picked up the mini mill/drill my intend was to get the lathes milling attachment. (The lathe's spindle is MT3).

564
Reply to
Searcher7

et. =A0You say

-4564

For informational purposes, here is another option.

formatting link
Darren Harris Staten Island, New York.

Reply to
Searcher7

uld not expect

unscrewing the

llet. =A0You say

threaded ring

38-4564

ero ---

Now it isn't "Adjust-Tru" but since it is on special I am considering finally picking this up.

formatting link
Thanks.

Darren Harris Staten Island, New York.

Reply to
Searcher7
[ ... ]

Can you get the backplate for it for your lathe?

Or can you make your own backplate?

I forget whether your lathe is a threaded spindle, or has bolts passing through the spindle nose flange to lock down the chuck backplate.

For example, the 1"-10 thread adaptor in 5" diameter listed in the "compatibility" section costs an additional $30.00

Hmm ... the "Micro-Mark" section says '3" flange' (which was what I was afraid of), and that sends us to an adaptor for a 5" diameter chuck which costs $28.95.

Call them and make sure that you get the right combination of chuck, backplate, and possible other things for *your* lathe.

Note that if the concentricity is not correct, you can't easily fix that unlike with the "Adjust-Tru" feature. It all depends on just how accurate you want your collets to be -- but usually collets (with the right adaptor) are the choice for concentricity

Good Luck, DoN.

Reply to
DoN. Nichols

Yes. LMS sells them.

That's something I have to learn.

formatting link

The 5C collet chuck uses the same adaptor plate as the 5" 4-jaw chuck I was going to get.

formatting link
I say "was" because I wanted the option of mounting the same chuck on my rotary table which will no longer be the Phase II they have since I've now won a Vertex on eBay. (I should probably be thinking of a slimline chuck for the rotary table anyway if I can make an adaptor for it).

Reading between the lines, since I have that 5C collet chuck we discuss a couple weeks ago,..

formatting link
...the LMS chuck wouldn't be worth it and I should instead make a larger jump to one with "adjust-Tru" when the time comes, correct?

564
Reply to
Searcher7

Good!

And for this style, it is a little trickier than for a threaded spindle nose. Here, you have to make a recess which is a good fit on the boss on the left-hand end (as shown in your URL below), and then drill and tap three or four holes, depending on the number of jaws on the chuck (though with a backplate, I would go for three holes no matter what). That spindle nose has 6 holes patterned so either a three-hole pattern at 120 degree intervals, or a 4-hole pattern at 90 degree angles will work, with one hole serving in both patterns.

You need to make either a three-hole or a four-hole pattern to match, and without the rotary table and the ability to set the mill spindle precisely to the right radius, it is easier to use a spare spindle (such as the above) and use centering punches sized to fit the holes to mark the holes you need -- then drill and tap them without letting the holes wander.

O.K. Given the rotary table, and the lathe, you can probably make an adaptor plate which centers on the table, accepts the chuck, and bolts to the table's T-slots.

Yes. Of course, none of these would be necessary if you had a large enough lathe to accept the 5C collets directly in the spindle nosepiece, or in an adaptor which fits the spindle's internal taper.

Good Luck, DoN.

Reply to
DoN. Nichols

huckbody which go into the threaded holes which the backplate normally

564
Reply to
Searcher7

If the question is, "Is a 6-jaw as versatile as a 4-jaw?" the answer is an emphatic "no."

Reply to
Ned Simmons

A 6 jaw is generally the same type of chuck as the 3 jaw. But it has double the number of jaws, for when you need to chuck up thinner stuff..it tends to "dent" the work less and hold better. But its not a do all life saver. But its damned nice to have.

Gunner

Reply to
Gunner Asch

Right.

You can hold rectangular things with 3 or 4 jaws of the 6. Using 4 will center one side, which is one more side than a 4-jaw chuck automatically centers.

Reply to
Richard J Kinch

Only if self-centering is not an element of versatility.

Reply to
Richard J Kinch

[ ... ]

[ ... ]

As for maximum gripping size -- does it come with a set of reverse jaws? The one which I have does not have the reverse jaws, so I am somewhat limited there. (Also, if it comes with two-piece jaws, you can reverse the top jaws and get the same effect.)

As for the through bore -- that doesn't make much difference unless your spindle has as large a hole all the way through it. Without that, you simply can handle things only with a little greater extension into the body of the chuck.

Sure -- as long as it is enough smaller than the rotary table itself.

Probably so -- but tricky to set up. And for handling things like irregular shaped objects, or turning an eccentric (such as the bearings on a crankshaft for a model engine) -- a 4-jaw is really hard to beat. Worry about getting a 6-jaw later, when you need to turn thin-walled cylinders.

The same can be done with a 3-jaw of course -- and it could be done with a 4-jaw, but there is no point to that, unless you have a "universal" (scroll-plate operated) 4-jaw, and those are rare.

And the first trick (before trying to make a 6-jaw chuck into an adjust-tru type) is to try making a back plate for your spindle, since it is different from the threaded ones which are easier to make. If you can make one which centers accurately every time you install it, then the rest of the project is within reach.

Good Luck, DoN.

Reply to
DoN. Nichols

Ive got a number of 6 jaw sets, both ID and OD. What is your chuck?

Ive got probably (15) 3 and more jaw sets, that dont fit any of my chucks. Most of them are new, or new new.

If anyone needs any....

Gunner

Reply to
Gunner Asch

I don't think it comes with reverse jaws. Here it is on eBay:

350358162918

Well my 7" x 14" lathe only has a .787 dia spindle bore.

formatting link
The spindle taper is MT3 so are MT3 collets the next best thing as far as repeatability compared to something with adjust-tru?(Or am I not understanding things correctly?).

My biggest issue is turning stock to diameter and then flipping it around and turning the other end without too much trouble with the issue of Concentricity.

Well, it's a 6" rotary table, so that shouldn't be a problem.

Ok, I guess it's back tot he independent 4-jaw. (I do have a lot of Delrin and nylon to turn).

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0I

Thanks. I was actually just reading about a back plate project.

formatting link
Darren Harris Staten Island, New York.

Reply to
Searcher7

Great! I wonder what the odds are?

Bernard Pratt:

BP69/40883 (I suspect that after the slash is a serial number)

OD: 6.318" 160.40 mm

Jaw dimensions:

Jaw set Number: 3684

OAL: 2.471" (the outside jaws may measure somewhat different)

Width: 0.743"

Width in grooves: 0.449"

Groove width: 0.309"

From bottom of groove to end of teeth: 0.278"

TPI: 0.250"

My e-mail above is valid, but I've got a lot of IP addresses blocked, so if the first bounces or gets no answer, try from another of your e-mail accounts. Or, there is always the phone in my .sig below.

Certainly -- if we can find a match.

I had trouble finding a match in the Bernard Pratt jaws catalog, so I don't even know what they would charge for a set. :-)

BTW I met Howard Taylor (writes/draws _Schlock Mercenary_) last Saturday. He was at the Baltimore Science Fiction Convention and I picked up three of his dead-tree editions of the comic.

I know that you enjoy that one from something posted a few years back -- which I think is what steered me to that comic.

It is amazing how fast he can do the sketches in the back page. Two for me, one for my wife. Doc Bunninga, Elf (version w/small legs), and Schlock himself.

And he is a great guy.

Thanks, DoN.

Reply to
DoN. Nichols

That one not only does not have the reverse jaws, it has an unusual set of jaws -- a lot deeper than normal. They would be good for holding a long thin-walled cylinder, but not for much else.

The web page you point out below shows a set of normal jaws on a

6-jaw chuck part way through the project.

So -- the best that you can do is the larger parts up to the depth of the chuck body. (Not the distance to the backplate, because if you make an adjust-tru style back for it, the backplate will be on the other side of the spacer ring, but the projection inside will take up most of that extra space.

The collets should be better than the adjust-tru -- and certainly don't need to be re-centered every time you change workpiece diameter.

You need to learn to turn between centers. *That* is the best way to deal with that. Do you have headstock center and tailstock live center? Do you have a lathe dog and a dog driving faceplate? If so, then you have all you need to handle long workpieces which need to be reversed -- assuming that you can live with a center hole drilled in each end.

Right.

[ ... ]

Also -- a 4-jaw independent can help you to bore a hole quite a ways off center at need.

[ ... ]

O.K. He did some things in ways that I would not -- including turning the quick-change toolpost at 45 degrees when turning the taper. This presented the edge of the insert tool at an angle which might not have had enough relief.

Also -- I would have started by boring the center hole, then marking the desired locations for the camlock bolts (perhaps with transfer bolts and a plug which is a sliding fit on both bores), and then face and turn the centering spud for the chuck.

And I would have made three threaded holes in the backplate for using screws to jack it out from his shrink fit.

But -- everyone does things the way which makes sense to them.

And how much is his spindle like yours? I think not enough.

Enjoy, DoN.

Reply to
DoN. Nichols

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.