What Lathe Would You Like to See Built?

[toag]

I'm not giving up!
I have the tailstock fleshed out... sorta. going to make a few changes to the bed.

i have a question about having a lead screw and feed screw. I have both on my lathe, I thought the seperate screws were so the thread lead screw wouldnt get worn out. my idea is to make the feed screw run on. a stepper , I was thinking ball screw and nut for this... would I need a seperate feed screw, I was thinking of using one for both.

 

[wrmiller]

I was also told that the separate screws are to slow wear on the threading screw. But in larger lathes, wouldn't the separate drive screw also allow larger/heavier cuts? If this is true, then maybe a separate screw is not really necessary for a hobby lathe. But if you used a ballscrew, how would to engage/disengage the carriage?

Bill

 

[John Hasler]

I was also told that the separate screws are to slow wear on the threading screw. But in larger lathes, wouldn't the separate drive screw also allow larger/heavier cuts? If this is true, then maybe a separate screw is not really necessary for a hobby lathe. But if you used a ballscrew, how would to engage/disengage the carriage?

Bill

If you are trying to keep the cost down, don't. Just run the motor fast to traverse. Everything should be either 100% manual or 100% motor-driven. Try to eliminate gears, clutches. split nuts, and other machinery. Plastic nuts would be cost saver too.

 

[toag]

yeah i'm thinking it might not work like i want it to. more food for thought.
I'm not in a cost saving mode with this, more of a "get the bugs out and make it work" at least on paper. If i get to a point of making parts, then i'll get to cost savings.
I love the idea of dialing in feeds or threads on a touchpad (or iphone!) and having the stepper do the work. but i also like the idea of manually running the carriage most hobbiest enjoy doing.

I think there is a line between being a jack of most and a master of some. i'd like to find that happy medium. I'll hash on it some more, and get some parts in CAD.

 

[David Kirtley]

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?

The carriage locks don't have to be full length. They can be at the ends with the gibs between them.

 

[John Hasler]

yeah i'm thinking it might not work like i want it to. more food for thought.
I'm not in a cost saving mode with this, more of a "get the bugs out and make it work" at least on paper. If i get to a point of making parts, then i'll get to cost savings.
I love the idea of dialing in feeds or threads on a touchpad (or iphone!) and having the stepper do the work. but i also like the idea of manually running the carriage most hobbiest enjoy doing.

In manual mode you could control the motor with a couple of pushbuttons, a lever, or even a handwheel.

I think you'd probably want a servo rather than a stepper on the feed but it doesn't have to be expensive: any motor is a servomotor with closed-loop control.

 

[toag]

thats a good idea!

A pulse generator could act just like the carriage feed, and the cross feed could be a gear on the end of the cross feed ball screw. I'd would probably need help with the EE part of that, though for the near term, i could reroute a pendant.

ok i have another question: would it ee worthwile to have a power feed for the tailstock barrel?

 

[David Kirtley]

ok i have another question: would it ee worthwile to have a power feed for the tailstock barrel?

It might be even nicer to have the tailstock on a second carriage. I can think of some interesting things to do with that. (like a tool changer)

 

[toag]

It might be even nicer to have the tailstock on a second carriage. I can think of some interesting things to do with that. (like a tool changer)

thats pretty much what i am thinking! something along the lines of gang tooling as an upgrade

 

[gregdammit!]

It might be even nicer to have the tailstock on a second carriage. I can think of some interesting things to do with that. (like a tool changer)

that was one of the reasons behind the centralized feed screw... it could be used to pull the tailstock for feeding operations, which i'd prefer to having a driven quill. i've heard of machine's that have a method of connecting the carriage to the tailstock to drag it and i've heard of people mounting the tailstock in front of the carriage and pushing it. while clever, neither of these seemed very refined.

So how is the tailstock coming along toag?