Manual Lathe With Linear Bearings?

A

Andre

Forum Guest
Register Today
Ever since I got my larger lathe, the little AA 109 just isn't being used anymore and is taking up bench space. I can sell it for $250 or so, it's in darn good shape, so that's my budget. I'm thinking of building a small manual bench lathe to replace the 109. Possibly using fully supported bearing rail in the 12-16mm range, or track. I know a guy who deals with linear bearings often so I will ask his opinion on which to use.

I know a lot of homemade CNC lathes, routers, and mills use linear bearings and track but will they be suitable for a manual machine, where there WILL be backlash in the screws? Because linear bearings feel like they're floating on a magic sheet of anti-friction air I wonder if the carriage will bounce around, without a zero-backlash screw to keep it in place. Any opinions welcome.
 
Trust me, when it comes to lathes, mass and a little friction are your friends.
 
I can't qualify this with any first hand experience or cite any sources, but I spent a long time contemplating a DIY lathe using linear bearings as you describe. Enough reading and asking around led me to abandon the idea. I do not think linear rails are rigid enough. Well, they can be, but those that are, cost more than a new lathe, so it's really quite pointless.
 
You might be able to find some more info at cnczone.com. There are a lot of do it yourself guys over there. One concept is rails made from square tubing with bearings on all 4 surfaces. Many designs use skate bearings because they are so cheap. Roller bearings would have significantly more contact area. Ballscrews to position the rails would have very little backlash along with very little friction.

Steve
 
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.
 
Guess what, Haas lathes are linear bearing machines, all there machines are LB, main issue I see is locking the ball carriage to the rail to do facing cuts, otherwise a good 20mm rail and 2 carriages per rail would be fine as a bed. I wouldn't go any smaller than 20mm, you need to study up, to make sure you get the right ones, you need the ones with 4 ball tracks in the carriage
 
I got my bad ass bosch Rex Roth rails for like 300 bucks on ebay, they allow 19 inches of travel with a healthy spread between the carriages on each rail....
 
Does Hass make a manual machine? I think the linear bearings would only work with a Cnc. I could be wrong though. Another option for you could be using Turcite instead of linear bearings. I know for a fact its used on manual machines sometimes when they are rebuilt.
 
Ebel, no haas doesn't make a manual machine, but the TL1 can be ran manually.....
Turcite doesn't apply here, he's not rebuilding a machine, but rather wanting to build one from scratch, using LINEAR BEARINGS
The problem here is money, you said 250 budget? That's gonna be tough to accomplish
 
I know what he was asking. My point is Hass machines all use a motor to hold the carriage in place. Using a Cnc in manual mode is much different then a manual machine. Turcite was used in plenty of new machines and in my opinion would be better for a home built manual machine then ball slides.
 
You must log in or register to reply here.
Back
Top