What Lathe Would You Like to See Built?

[David Kirtley]

if you don't mind me adding my two cents worth

Hey, I'm the one dropping in. You started the thread

There are lots of workable configurations. There are often no real stand out *best* solutions. Boxed, dovetailed, prismatic, and tubular ways have all been successfully implemented. Each has benefits and drawbacks. Some scale better than others. Some are easier to build. Some are easier to maintain. Some use materials more efficiently. Some are cheaper to manufacture. Some are prettier.

The main controlling factors that I use in my case are cost and feasibility of construction. I don't have the capability of casting metal of that size in my home so that is out of the picture. My options for the structure are steel, aluminum, wood, cement or epoxy based aggregate, or fiber based composite (or some combination of these.) Other than wear surfaces, you could make an equivalent strength structure from any of them. For that matter, you could make a structure out of wood that would be just as strong as from cast iron. It would just take a lot more wood.

 

[sinebar]

Build it with ballscrews.

jj

 

[wrmiller]

Build it with ballscrews.

jj

Forgot about this one. I'm tired of hearing the misinformation (this in particular, there are others) that you can't use ballscrews on a manual machine because the table will walk, feed, whatever. When first learning, I was told that it is best to lock any/all axis that your aren't moving on during a cut anyway, even with acme screws.

So instead of locking the table with traditional screws, I figure to lock the the ballscrew with a quick release clamp instead. Same principle of having a stepper motor holding a screw in place that isn't traversing, or a screw jammed into a gib. I get smoother motion and no backlash. Best of both worlds?

Bill

 

[gregdammit!]

Forgot about this one. I'm tired of hearing the misinformation (this in particular, there are others) that you can't use ballscrews on a manual machine because the table will walk, feed, whatever. When first learning, I was told that it is best to lock any/all axis that your aren't moving on during a cut anyway, even with acme screws.

So instead of locking the table with traditional screws, I figure to lock the the ballscrew with a quick release clamp instead. Same principle of having a stepper motor holding a screw in place that isn't traversing, or a screw jammed into a gib. I get smoother motion and no backlash. Best of both worlds?

Bill

i have an idea for a quick release full width carriage lock that grabs both outside rails and pulls toward the center. maybe even add a chamfer to the underside of the rails to help draw the carriage down to the frame. that way we'd get a super stable platform for facing operations, not to mention how it should help with stability for milling operations. no tools needed and there shouldn't be a chance of marring up the bed ways.

with a set up like that, any type of lead screw would be possible... thoughts?

 

[wrmiller]

i have an idea for a quick release full width carriage lock that grabs both outside rails and pulls toward the center. maybe even add a chamfer to the underside of the rails to help draw the carriage down to the frame. that way we'd get a super stable platform for facing operations, not to mention how it should help with stability for milling operations. no tools needed and there shouldn't be a chance of marring up the bed ways.

with a set up like that, any type of lead screw would be possible... thoughts?

Not sure I'm visualizing it, but it sounds interesting.

Bill

 

[toag]

Had some time at lunch to do some more tweaking. added flares to the base (i think they are good spots for attaching motors and whatnot. We will definitely use steppers for threading, just soo much cleaner and would be that much closer to cnc. made the bed a bit deeper to accommodate possible center lead screw, still fits in a 8x36 casting, was trying to keep in that footprint. removed the ellipses (though i thought they were cool) for some straight obround holes to help weight. its a svelte 200 ish bls now, and can trim more easily.

.


cant attach .stp files for some reason, greg, PM me an email, and i'll send it to you.

 

[David Kirtley]

I'm tired of hearing the misinformation (this in particular, there are others) that you can't use ballscrews on a manual machine because the table will walk, feed, whatever.

Bill

I think that this comes from people that have only seen the ball screws with the extreme pitch for speeding up movement and not realizing that they can be had on finer pitch screws as well. Would I put a 0.5 tpi ball screw on a manual machine? No. 5 or 10 tpi ball screw? Sure anytime.

 

[gregdammit!]

ok, so this was some down and dirty modeling, i know it doesn't show a lot of detail, but it should convey the basic idea of the locks. the green is a carriage profile, the black is a bed profile, the little red triangles are linked together so when the lever is cammed it draws the two together against the bed. they could either be full width of the carriage, one at each corner, or one side stationary and one movable. the only other question is whether to make this separate from the carriage adjustment or use it in place of.

hopefully this will help to visualize what's a little difficult to explain...

 

[eightball]

Where would the gibs go? All the lathes ive ever seen have gibs beneath the carriage. Nice idea, maybe having the locks inside the ways, and the gibs outside?

 

[GadgetBuilder]

Here's a home built lathe incorporating lots of interesting ideas: Stepperhead

http://www.lathes.co.uk/stepperhead/

John