[kong]

Hiya guys, I have just bought a 1963 Colchester Chipmaster lathe which would be perfect for CNC retrofit. Unfortunately my father has grand designs for building steam engines and such in the evenings
I am therefore trying to think of an "easy on, easy off" cnc attatchment.
Now this lathe comes with a big ol' taper turning attatchment which has it's own leadscrew and can be hooked up in about 10 minutes (Photos will come if thee is any interest in this thread). So I am thinking of using this attatchment, hooking a motor to it for a removable x-axis. One thing I need to point out here is that the current leadscrew has a backlash of 0.15mm - plenty accurate for the RC alloy wheels I make, so no need for ballscrews at present. One thing I cannot figure out is what tpe of bearings are inside the attatchment, and whether they will hold up to the task. If not, I will simply use the leadscrew, but add new bearings. Any opinions would be greatly accepted, and plans for the z-axis will be posted shortly (I am working on them).

[JFettig]

I have built a very nice mini lathe bolt on setup, If you dont see what you want in my gallery, i can show you some closeups privately, PM or e-mail me

Jon

[kong]

Cheers Jon, unfortunately I can't find the end of my leadscrew to bolt a servo onto!



I am thinking of something easier to remove. Here is a piccy of the taper attatchment, it sits on the back of the saddle, and has it's own leadscrew which can be removed easily.



You see the round piece under the crossslide, well that is the end of the leadscrew. It should be simple enough to mount a motor to it, and have a removeable assembly. I have forgotten the shot of the bearings haven't I

Oh well, here is one more of the whole lathe just for fun.

[JFettig]

You can always mount to the other end, drill and ream and press fit a shaft into it to mount a motor to. many ways

Jon

[kong]

Lol, I was playing, I have no intention of using the existing leadscrew.

The plan for Z is to use a new leadscrew, bolted along the rear of the bed via bearing blocks, with a motor mounted on the end as per usual. The difference being I will use a quick release coupling to engage/dissengage the nut from the carriage. I am thinking along the lines of a dovetail quick change toolholder. The body of the toolholder (or something similar in shape, you get the idea) would be bolted to the carriage, and the holder would be attatched to the leadnut. A quick flick of a wrench, and the two part company allowing me (or my father) to regain use of the handwheels, screwcutting, etc, as he would need to since he is "too old for new fangled CNC business".