The Home Machinist!

Shortly after I got my JET 1236PS lathe, I fitted it with a 5C collet chuck, from which I've gotten plenty of use since.  Along with the lathe, I received various odds and ends, not all of which I had inventoried at the time.  They had been in a box on a shelf for the last several years.

Recently during a shop cleanup, I decided to look at the odds and ends and decide if I should keep them or get rid of them.  Much to my surprise, one of the items turned out to be an MT5-to-5C collet adapter sleeve.  It’s a precise fit into the spindle’s bore and a 5C collet fits in it.  JET didn’t list it as a standard accessory in the manual, which is why I was surprised to find it.

Anyhow, mounting a collet directly into the spindle would have several advantages over using the collet chuck, not the least of which would be very low runout.  Obviously, I will need some sort of collet closer.  I'm not using this lathe for any kind of drawn-out, repetitive tasks, so whether the closer is lever-operated or uses a wheel doesn't matter.  I should mention that the bore through the spindle is 1-1/2".

I’ve entertained the thought of tracking down a draw tube that has the necessary internal thread at one end and then making the rest of it.  However, I really don’t want to expend time manufacturing a collet closer.  Modifying something made for another lathe might be practical, but doing it from scratch is out—I’ll stick with the collet chuck if I can’t buy something reasonable.

Any suggestions?

Use what you have that works, and sell the other items.
((-;
RussN

Don't be so lazy ! Get a piece of seamless tube ,cut a internal thread ,buy a thrust bearing from McM/C ,whip up a handwheel. I have seen pre threaded tube available . Not a big project ,made several for a couple of lathes I have had. Look on eBay as over the years I have seen several handwheel draw tubes on there. But you will probly find it cheaper to build your own . Jet obiviously used standard MT-5 and those adapters are common ,not like South Bend and Clausing to name a few that used none standard spindel tapers.

I have made several as John has described above...it is a standard tube size...

after about 25-30 years of hard use, the threads get wonky...

no, I have never bothered to harden any of the threads since 'this will last as long as I am going to live'........

fortunately, i have been wrong on 2 occasions (2 different lathes with 2 different length pull tubes - identical other than that).

before you use the adapter, be SURE you have a spindle saver nut / extractor. They are a bear to get out otherwise...

John Evans wrote: ↑Wed Feb 01, 2023 1:09 pmDon't be so lazy !

It’s not a matter of laziness, but time.

I’m not in good health anymore and can’t tolerate the “long burn” I used to be able to do in the shop.  As I tire relatively quickly, frequent breaks are a necessity.  I’ve got to be careful with overextending myself, as I’m usually alone in the shop while working.  I don’t want my “landlord” coming into the shop some morning and encountering flies buzzing around a cadaver.

Bottom line is I have to pick and choose what I do to maximize productivity.  The goal is to complete the F-unit project, not tinker with machine tools.  I’m way behind the eight-ball with the F7—it should have been done 10 years ago.  Make parts for the lathe so I can make parts in the lathe will only worsen things.  A few years ago, such a diversion was no big deal.  Now it is.

My question was that of asking for suggestions on a collet closer solution that doesn’t entail the manufacturing of a bunch of parts.  As I said in my lead post, I’m okay with modifying an existing closer to fit my lathe, if it’s practical to do so.  If I do have to go the manufacturing route, I’ll just stick with the collet chuck.

I hear you in the concerns..well into that stage of life also

Maybe purchase a closer tube that may be too long, and be prepared to make a sleeve or move the handle.

It is easy to approximate the needed length with a broomstick up the spindle with a collet in place

https://www.ebay.com/itm/115564411949

Steggy wrote: ↑Wed Feb 01, 2023 6:14 pmMake parts for the lathe so I can make parts in the lathe will only worsen things.  A few years ago, such a diversion was no big deal.  Now it is.

Having said that, I caved in to my innate urge to carve up metal into hopefully-useful objects and have started on making a collet closer.  Here's a simple design drawing of the closer:


Constituent parts are the draw tube, spindle adapter, hand wheel and hand wheel arbor.  The hand wheel will be made from a piece of 3/4" thick aluminum.  The remaining parts will be from cold-finished steel.  Here are some more drawings:


The lathe is specified as having a 1.500" spindle bore.  As the spindle adapter has to be a precision fit to the spindle bore so that everything runs true, I carefully measured the bore with a telescoping gauge and micrometer—the bore is actually 1.528".


The draw tube I have is nominally 1-3/8" outside diameter, but actually measured 1.377".  Being DOM tubing, this slight oversize is not unexpected.  The hand wheel arbor will be bored to a slight interference fit between it and the draw tube—I'm going to try to achieve a light press fit.  The outer end of the draw tube will then be anchored to the arbor with some small welds.  The hand wheel will be secured to the arbor with three 1/4"-20 socket screws.  I'll have to figure out how to machine the rim of the wheel to make a comfortable hand grip.


The spindle nose guard will double as the collet adapter extractor.  A wrench that I will have to make will be used to back out the guard and force the collet adapter out of the spindle.

I should have some parts photos soon.

I had a shorter draw bar for My 5c collet setup. I added the needed length and Locktited the tube in place so it could be changed in the future.

mcostello wrote: ↑Sat May 20, 2023 9:22 pm I had a shorter draw bar for My 5c collet setup.  I added the needed length and Locktited the tube in place so it could be changed in the future.

I found a guy on eBay who is producing 24"-long draw tubes from DOM stock.  I purchased one from him and am pleased with what I got—it’s a precise fit on a collet.

In my application, the finished length of the draw tube will less than the length of piece I’ve got.  The way in which I’m going to attach it to the hand wheel arbor will make it a semi-permanent assembly.  A worn tube could be replaced by cutting the retention welds and then pressing the tube out of the arbor.  I had considered attaching the arbor to the tube with setscrews, but have had unpleasant visions of the setscrews working loose, and the hand wheel and arbor going into orbit while the lathe was running. 

I expect that by the time the threads in the collet end of the tube have worn to where replacement is needed, I’ll be long gone—it’ll be the lathe’s next owner’s problem. 

Continuing where I left off, I’ve got some parts made.  First are some photos of the spindle nose guard:


The guard seats against, and completely covers, the spindle’s register face, protecting it and the spindle’s threads from low-flying chips and other assorted debris.  The MT5-to-5C collet adapter I have has a large flange on it that overlaps the end of the spindle and the face of the guard.  Hence the adapter’s flange protects the face end of the spindle.

Since the collet adapter will wedge itself tightly into the spindle with use, the nose guard will do double duty as the adapter ejector.  I've got a wrench I made for the purpose that fits onto the flats milled into the guard.


The wrench is made from a piece of 3/8" thick hot-rolled, P&O steel.  It’s not quite done—I need to make a handle for it from some round tubing, plus get rid of burrs and sharp edges.

Next step will be to machine the closer’s spindle adapter.  I was hoping the cost of raw materials would come down post-COVID, but it doesn’t seem likely.  Nevertheless, the finished closer will be much cheaper than the ones I see being sold.

Very nice

This is a timely thread as I just purchased a Jet 1236PS and would like to build a collet system for it. Until recently I was spoiled by the Hardinge lathe at my work (recently moved to a new job) so I've grown used to using collets.

I'll be following along to see how the rest of your system turns out. Looks great so far!