Manual Lathe With Linear Bearings?

[John Hasler]

With a CNC system there is always the Servo or Stepper motor holding the shaft in place very firmly where it is set. Not just set in place to be easily moved but set and held hard. With manual lathe there is nothing to hold place so the bearing will drift easily maybe easier with better bearings. For that reason ball bearing or any type of bearing should not be used on a manual machine. The shape of the stock threaded rod is made to hold its place for the most part. Set something to make a cut and let it cut with stock screws it is fine. With a bearing screw and without holding the shaft somehow it will move.

One exception might be to place one axis and tighten it down firmly while the other axis is actively cutting.

You could also add some sort of anti-backdrive brake.

 

[chevydyl]

Right, my mill has turcite, but it also has big dovetail ways.... so he'd have to construct the machine that way to use turcite, or even box ways, that type of construction unless he has a machine large enough to make them, it can get spendy. Friend of mine made a machine with Teflon coated ways using dovetails, made of plate, it held 2 die grinders that would cut on two parts at a time, with a rack and pinion movement, single slideway, the customer owed like 5 grand for it, and was happy to pay it. Not to say it can't be done alot cheaper, especially if your just having the angled steel made.
And as far as haas, yes the motors hold it, because it uses pulse generators on the axes for movement, BUT the tailstock has a lock....
When I run my mill manually I don't need to lock anything...

 

[Ebel440]

Using Turcite wouldn't require dovetailing the bed. I see no reason why the ways would need to be any larger then what linear bearings would require really. A T section shape made of ground bar stock and bolted together should make a usable way and if used in pairs as ball slides are it should be plenty. The bed could be the same as used for ball slides. Teflon couldn't be used instead of Turcite for a lathe as its much too soft and would be pushed out of the ways. Possibly uhmw but I still think it may extrude it out.

 

[chevydyl]

so how would you use the turcite? are you talking turcite BUSHINGS? if so then I agree, I was thinking we were talking turcite sheet that is applied to flat surfaces of ways, box or dove

 

[Jester966]

I built my manual milling machine using linear ways and 3/4-10 ACME screws. I have no issues with it.
The axes (axi?) all have gibs which bear against the side of the hardened rails and are set with fine thread SHCS's.

For a lathe the size of the 109, 15mm rails would be more than suitable. $250 is not very much for the whole machine, but you should be able to pick up the linear guides for a decent price off e-bay if you're patient.