Micro-lathe CNC

[jallitt]

more of an experiment than anything - it'll be interesting to see what happens when I start turning aluminium with it

http://www.b26354.co.nz/CNC/pictures/dsc_2268.html

if you work your way back through the gallery there are some in-progress pics.

Replaced the leadscrews with M8 threaded rod supported in bearings and made some delrin nuts (which were drilled undersized and are quite tight). I want to rearrange the way the Z-axis nut attaches to the carriage because there's too much backlash introduced from the flange on the nut flexing where it attaches to the carriage.

The cross slide motor bracket works really well (it's CNC milled from delrin with an aluminium plate bolted to it and a bearing mounted in the middle). There's a boring youtube vid of the cross slide moving here:

"http://www.youtube.com/watch?v=lDBFfPLQUoM"]http://www.youtube.com/watch?v=lDBFfPLQUoM

[NEATman]

Cool!
I have a small lathe just like that I was considering doing the same treatment to use as a demo. Do you have models/prints for the parts that you would be willing to share?

NEATman

[Regnar]

jallitt, I was just wondering how you like your C0. I joined the yahoo forum and it seems that people are really unhappy with them. Infact the letter from the forum moderator even suggested not to purchase them. I would like to go the same route as you with cnc it. I guess would you do it again knowing what you know now? What size steppers did you use? Thanks Regnar

[jallitt]

If you read through the "CNC for C0" thread on the yahoo group you'll see a description of my progress.

As a learning experience it was worthwhile - like it's better to have the Z-axis motor on the left so the thrust from the leadscrew pulls into the lathe rather than pusing into the stepper motor. Biggest problem is the carriage twisting when z axis changes direction which makes for some horrendous backlash at the tooltip (even if you have 0 at the leadscrew) but, since 99% of the time, you always cut in the same direction it's not an insurmountable problem as long as the toolpath has some leadin.

Since I'm just making model parts extreme accuracy wasn't required but multiple copies of the same part are required e.g needed 16 of these:



which are 4.55mm diameter and I ran the whole lot out in about an hour (which included manually drilling a pilot hole and countersinking the ends of each one)

Also for turning larger diameters a smaller pulley on the motor is useful - it's pretty easy to stall the motor on 2" diameter stock.

Not sure how much use the C0 is going to get though - I just picked up a old-ish manual Emco compact 5 which looks like a breeze to retrofit. And I just added a cncfusion kit to a sieg super X3 which means all my stepper mounts can be aluminium.

BTW sieg have the KC0 in their 2008 catalog:

jallitt, I was just wondering how you like your C0. I joined the yahoo forum and it seems that people are really unhappy with them. Infact the letter from the forum moderator even suggested not to purchase them. I would like to go the same route as you with cnc it. I guess would you do it again knowing what you know now? What size steppers did you use? Thanks Regnar