Hi,
for most of my work I use a 3 jaw or 4 jaw chuck, and I like to have available the full D1-4 bore for longer bars most of the time. However, occasionally, I would like the precision of a 5C collet in the spindle. For example, this morning I made a tool holder for my 1100 mill from one of Tormach's TTS blanks. I had to clamp the hardened 3/4" TTS shaft into the 4 jaw chuck and adjust for half an hour before I had a reasonable precision. With a 5C collet, that would have been a one minute affair.
Tormach's 5C collet closer is nice, but one has to remove it for chuck work, and in my case the $1000 tool would sit in a closet almost all the time.
So I wonder why not make my own draw tube? 1.25" thick wall steel tube, cut collet thread into one end, cut outer thread the other end, make a nut for that outer thread that pulls the tube "in", keeps the tube centered, and is deep enough to be accessible from the outside. Any reasons that shouldn't work? Has anyone done this before? Or can I buy it commercially?
Thanks,
Stephan
I don't have a slant pro, or any cnc lathe for that matter, but this is a common DIY project for manual lathes, I made one years ago for my 13" enco and it works well. I'm sure if you goggle it you will find lots of examples.
I'm not sure what the native taper of the slant pro spindle is, but most manual lathes are not 5C so you install an adapter to match the taper, should be readily available, if needed. Mine was 5 morse and I had no trouble finding the adapter.
Hi Terry, all,
Terry, thanks for your advice.
I spend a few hours today and the result is shown below The drawbar works fine; and can be tightened easily and sufficiently using the machined nut and a band-clamp on the spindle nose. To use it, one has to remove the chuck, insert the taper (which comes with the Tormach lathe, insert the drawbar, hand-tighten the collet, insert material, and fully tighten the collet. With some very limited practice, it takes me 2 minutes to change from collet to chuck and vice versa. I used leftover material; in particular 2.5" bar stock about 4" long (from the leftover box) for the nut, and a length of 1" schedule 40 galvanized pipe for the drawbar itself (that I was about to throw out). The threads are the same on the collet and nut side: 1.25" and 20 tpi. In an ideal world, I would replace the schedule 40 pipe with something a bit more balanced, but since the maximum RPM of the Tormach when using the chuck setup is not all that high, I think I will forego that.
Stephan
5C draw tube for occasional collet work
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