Thoughts on giong the Collet route...

[GaryK]

Gary, if I'm not mistaken, the make is "Strong". It's not a big name, I suppose, but it's a 10" that came with the lathe when I bought it new. It's never been off, and never wrecked. I'm beginning to see a little "spring" if I don't use the entire length of jaw, but I can just toss a piece of round stock in and I'm surprised if it's more than 0.0015 or so. I do use almost exclusively the marked primary pinion for tightening, and have pulled the jaws and solvent washed the scroll regularly, and kept it lubed. If I ever replace it, it will probably be a Buck 6 jaw Set-Tru, but I don't envision that any time soon. That chuck is about 15 years old now, I believe. I could probably touch it up with a TPG, but it is still plenty accurate for my work.


I am in no way putting down collets, and as I said, not trying to talk anyone out of going that route, but just pointing out some alternatives, and some of what I consider weak points that can easily be accommodated with soft jaws. Both have their places, and it comes down to what kind of work you want to do. Kind of in the same vein as the thread on what doesn't make you a machinist. Collets are not a cure-all or panacea for lathe workholding. And there are many things that you cannot do with them that you can easily do with a self centering chuck.

Tony, I'm sorry, but I think you took something I wrote, wrong. In fact I didn't read the other postings after my initial post. I just saw this back at the top of the list and remembered some other things that I liked about collets, hence may last post. Sorry for my misunderstanding.

Gary

 

[Tony Wells]

Gary,
don't worry about it. I was only trying to make sure I wasn't misunderstood. No harm, no foul.

 

[Ray C]

Tony... Thanks.

I think you got your moderators mixed up. I was the one asking about the make of your chuck. I review so many threads, I get names mixed up too. BTW: I love the convenience of a 3J!

OK. End of hijack.

Back to topic.... I totally agree and don't think you were putting anything down -just adding a different viewpoint -and a totally correct one at that. Collets are not the cure-all to end-all. As we've all mentioned, they have their application and shine in some areas and fall-flat in others. When I get boat shafts, it's usually 2-3 at a time and they're all the same dia and the motor end is finished. -Perfect application for collet.


Ray

Gary, if I'm not mistaken, the make is "Strong". It's not a big name, I suppose, but it's a 10" that came with the lathe when I bought it new. It's never been off, and never wrecked. I'm beginning to see a little "spring" if I don't use the entire length of jaw, but I can just toss a piece of round stock in and I'm surprised if it's more than 0.0015 or so. I do use almost exclusively the marked primary pinion for tightening, and have pulled the jaws and solvent washed the scroll regularly, and kept it lubed. If I ever replace it, it will probably be a Buck 6 jaw Set-Tru, but I don't envision that any time soon. That chuck is about 15 years old now, I believe. I could probably touch it up with a TPG, but it is still plenty accurate for my work.


I am in no way putting down collets, and as I said, not trying to talk anyone out of going that route, but just pointing out some alternatives, and some of what I consider weak points that can easily be accommodated with soft jaws. Both have their places, and it comes down to what kind of work you want to do. Kind of in the same vein as the thread on what doesn't make you a machinist. Collets are not a cure-all or panacea for lathe workholding. And there are many things that you cannot do with them that you can easily do with a self centering chuck.

 

[dfwcnc]

Excellent. Can you link me??

Couple thoughts... If you go that route, completely avoid using a collet too small for the shaft and attempting to clamp it tight. The collet could get stuck and it could deform the very outer lip of the inner hole. A full set in 1/64 steps is ideal. Also, the bore will get scored-up if you work on scaly metal so, I only put clean stock in them.

BTW: I got mine from shars. After proper mounting the needle on the TDI doesn't move. Not bad for something like 125 bucks -as I recall.

Ray

I have an Atlas chuck (4-jaw) and a Buck Chuck (3-jaw). I use the Buck as it's nicer and easier to use and center. And like you say, they are leaving bad marks on my work piece which are unacceptable. The largest diameter I'll be working with (for collets) would be 3/4, and that seems to be an issue.

Independent jaw chucks are notoriously unrepeatable. If you remove the work, don't plan on getting it back in the same way again. You can get things dialed in dead on with an independent jaw chuck (at the expense of time). Collets are another option. Usually more expensive, they are nice because they have good concentricity, and they grip over a large area, which is nice for thin or fragile items (they mar less than a chuck).

There are a TON of different types of chucks out there. Probably the most popular for workholding in a lathe is the 5c collet. This is what you seen on Hardinge lathes (they invented them, or purchased the company that did, can't remember), and the spindle of those machines is a match. You can also get lots of accessories that use them on the mill (spin indexers, collet blocks, etc). They are also common, so you can probably pick them up used on E-bay if you are patient. The downside of them is that they have a very small clamping range, so you need a lot of them to cover the full range.

It somewhat comes down to what type of lathe you have. In any case, you will need a collet chuck, which you can make or buy.

Happy to, I have an Atlas 618 with a three-phase motor (1750rpms max) being run by a VFD, new lead screw and half nut and rear gear along with other small parts. It runs really well. I was asking about a Myford and have decided to look for the "Super 7" in addition to my Atlas. I am interested in both the MT Collets and the Collet Chuck. Which ever gives me the largest hole, and the most options.

dfwcnc,

It might be well, since no one else has mentioned this, to back up and say that what kind of collets are practical for use depends upon what size of machine you have or expect to have. Second, a collet chuck is a relatively complicated widget that attaches to the spindle in the same manner as any other chuck and generally is tightened with a T-handle wrench. Everything else is more commonly called a collet closer (except with MT collets which fit the native spindle taper and only require a drawbar) and are either lever and drawtube or handwheel and drawtube actuated. So what machine are we talking about? Several threads ago, you mentioned having an Atlas 618 but asked about a Myford.

Robert D.

That looks nice. I wonder if those would work on an Atlas?

5C collets aren't limited by when can fit through the collet. You can get clutch collets up to 6" in diameter for large shallow items.

View attachment 48217

You can also take these and machine square or offset parts in the mill to hold them in the lathe.
They also make collets for holding on to the ID of parts.

You can also use them on the tool post of your lathe to hold endmills Like I did here:

View attachment 48218

5C collets are very versatile. These are just some of the things you can do with them.

Gary

 

[Ray C]

Excellent. Can you link me??

QUOTE]

http://www.shars.com/products/view/856/5quot_5C_Collet_Chuck

Also look at eBay for seller "Discount Machine" -same company (Shars) and they often sell the chuck for $175. Mine is several years old and the overall price was lower then. Search eBay and you'll see plenty in the $175-200 price range.


BTW: On a 618, you might be better off with a 4" chuck. Both hold 5C collets and a 4" is probably a better size for that machine. Shars only sells 5". 4" tend to cost more.


Ray

 

[GaryK]

That looks nice. I wonder if those would work on an Atlas?

I had a 5C collet chuck on my Atlas.

You can see it on the bottom shelf on the left next to the milling attachment. You can also see my 3AT collets on the shelf under the lathe bed.

 

[stevecmo]

I'll cast a vote for ER collets. You can make your own ER collet chuck on your lathe. That was the first semi-complicated thing I made. It's also good experience requiring internal and external threading and taper turning. It's really not that difficult if you take your time with it.

To me the advantage of the ER collets is they allow long stock to pass thru the collet and spindle.

Just something else to ponder.

Steve

 

[kd4gij]

+1 on the er collets. I made an ER40 collet chuck for my craftsman 12" lathe. Er32 would probly be fine for a 6". ER collets have a little wider range than outhers and alot more clamping force as thay stay parallel to the work piece.

 

[Ray C]

Are the ER type suitable for holding endmills?

Ray

+1 on the er collets. I made an ER40 collet chuck for my craftsman 12" lathe. Er32 would probly be fine for a 6". ER collets have a little wider range than outhers and alot more clamping force as thay stay parallel to the work piece.

 

[stevecmo]

Ray,

Good question. The one drawback to the ER collets is that they really need whatever they're holding to be the full length of the collet for "maximum" holding strength. So it kind of depends on the length of the end mill. Having said that, I have used my ER-40 with end mills on my lathe on aluminum several times. Haven't tried it on steel but I think it would be fine light cuts - which you probably want when milling on a lathe anyway.

When I do light milling on my mini lathe, I use a shop made end mill holder with a set screw to prevent any slippage.

Steve