I bought the Tormach 6" tailstock. it can be easily modified to mount a live center on it.
I have the TTS M2 taper so i can use TTS tools in my lathe. If I make a mount for the tailstock I have the added advantage of using the same TTS tools in the tailstock for the Tormach. So that means one livecenter for both machines. I had not considered about less friction, but I did figure the LC would just be easier all around to use.
How would you go about modifying it? It did not look easy to do to me but maybe I am overlooking the obvious.
The existing center is held in place by two pins for vertical adjustment. Since I don't do a lot with heavy parts, I figured just a new block assembly that has a M2 taper machined in it made a aluminum would be sufficient. You would just need someway to push the M2 taper cylinder through for fine adjustment.
Now after looking at it... It might be easier just to make a mounting plate for my lathe tailstock and just move it to the mill when needed..... That way I would just have to account for the height issue. The Tormach tailstock (which can also be bought from enco as well) already has the height adjustment.
i considered making a bolt on block as well but since that would leave no way to feed it into the part I dont think it would work easily. Someone must make a tailstock that accepts a live center that will work. I guess I will keep searching.
No it doesn't make sense. You really are wasting your time worrying about this. The stress is absolutely minimal. Set it up with the dead centre, disengage the worm on the RT and see what it takes to rotate the table by hand. Then disengage the dead centre and check the reduction in resistance when you rotate the table by hand. Now engage the worm, run the table and try to stop the table by hand, no chance.
The table rotates face to face with the table housing, if you're going to use a live centre to reduce stress then maybe you need a roller bearing on the table to housing face also.
If this type of rotary table could benefit from a live centre then it would probably come already equipped for this, at least as an option.
Originally Posted by compunerdy
So using a live center to create less friction and reduce stress on the 4th axis does not make sense?
I obviously did exactly that and noticed quite a bit of drag from my dead center which is why I wanted to switch to a live center.
The table surface is contantly oiled unlike my dead center.
The 8" tailstock comes with the option to use a live center, I guess that one is designed to go 5000rpm?
On my 6" table I CAN stop it by hand at low speeds and I have been having issues with missed steps in one direction. This may be totally unrelated but it makes sense to me to reduce as much resistance as possible to reduce stress on the 4th axis and stepper motor.
I obviously did exactly that and noticed quite a bit of drag from my dead center which is why I wanted to switch to a live center. .
Then you have the tailstock adjusted too tight. Did you put a dab of grease on the end? In fact I think the best procedure for setting the tailstock is to wind it in until you just feel slight resistance when rotating the table by hand.
I guess experiences vary. I have an 8" rotary table (Vertex), converted from manual using the Tormach kit, plus a Tormach 8" tailstock. On one operation I forgot to release the table locks while engraving 360 graduations and number markings on the circumference of a 3" diameter. The RT/stepper motor didn't even notice. The operation was successfully completed with the table lock on.
If you are loosing steps you should talk to Tormach. You should focus on the core problem not try to minimise the symptoms.
I agree with Phil on this one that there should be no need for a live center with such a slow moving RT. Also with the live center one is adding runnout due to the live center bearings. The slow moving Tormach rotary table does not use roller or ball bearings so why is it necessary to require a live center with ball or roller bearings?
Is flood coolant used? If so then there shouldn't be excessive heat during machining and the expansion of a longer part should not tighten up against a dead center such as I have experienced when turning on a lathe using a dead center.
BTW I still use white lead that actually contains lead for lubricating dead centers. Can’t buy the stuff anymore in the USA with lead in it. After my supply of white lead is gone will probably have to go across the border to get the stuff. Seems strange that lead has been banned from all products except tire balancing weights, nowadays one can walk down almost any street and find plenty of toxic discarded lead tire balancing weights lying around.
Last edited by Don Clement; 09-17-2010 at 11:52 AM.