My new (old) lathe almost complete

[DAlgie]

The guy from PDMX is at the show right now, he's testing one with a Campbell breakout board to see if there's any problems there, I'll let you know what I find out.

[Brian Barker]

We ran one of Steve's (PMDX) spindle sensors on the lathe at the workshop... It worked good but the steppers on the lathe were a little small... Steve is taking a CNC Mill home from the workshop so he will be a little bit getting back to you.

Good luck
Brian

[DAlgie]

Got the spindle sensor working right. Steve Stallings of PDMX suggested using a 0.1uF capacitor between the 5V and the ground right at the sensor, this fixed it totally. I ran the crap out of it tonight, never got a problem, ran a threadcutting program, was great. Then went and tied all the cables up together, thought this might send it crazy again, no, was still fine, so i'm very pleased with it now. Time to work on the toolchanger now I guess.

[FPV_GTp]

hi

that is a nice piece of machinery u have made a nice CNC conversion , Im  keen on coverting a 1980's copy lathe that i have here at my workplace

im interested in using NEMA 34 HIGH TORQUE STEPPER MOTOR 1812 oz-in, ½” Single shaft with flat, 180

KL34H160-62-8A  Specification are on http://www.kelinginc.net/SMotorstock.html

KL34H160-62-8B ½” Dual shaft with flat

I know its over kill in the size of the stepper motors but thats meI like big things

I want spindle speed contol , and arrange say four different tools on the cross slide to have say like a tool change but not a tool change  if u know what i mean., the  software will select the required tool  for the rquired maching process , seen this setup on a small desktop cnc-lathe, niffty idea.

cheers

[DAlgie]

Should work out good, you will be able to use that large stepper direct drive for the saddle, Z axis. Note that I only needed a 400oz/in for the X axis, so don't overdo that one, but that motor will be the one that limits the voltage you can max out on. Make sure you get a .200" per turn ballscrew for the Z axis and you will be able to get .0001" resolution with a 10X microstepping drive, I used Gecko 201's, very nice drive. I increased my voltage a couple of days ago to 42 volts DC, it was 28 volt and I could only get 38"/ min rapid, with the higher voltage I now get 60"/ min. rapids and am about 20"/ min away from stalling speed. X axis is very fast at 80"/ min. for a small 7" travel with this voltage. Note that the steppers don't even get warm at this. You will need to remove the apron from under the saddle, these usually bolt on. Then need to make a stepper mount and should 2:1 reduce the X axis ballscrew so you can get .0001" per diameter. This lets you place the stepper under the saddle using a belt reduction drive and makes a tidy package. I sealed the entire belt drive enclosure from coolant leakage, which is a must, at you need at least chip protection if you won't be using a flood coolant system. Make sure you add a cover above the Z axis ballscrew to stop the chips from dropping into it. Will be a fun project.

[DAlgie]

Just for reference, I think a good rule of thumb is that the Z axis on a lathe should have three times the power that the X axis has. Mills often get away with similar motors on at least the X and Y axis, but a lathe has a lot more weight to move around with the whole saddle than it does with just the cross slide. Also, you have a long, heavy ballscrew on the Z axis that you have to accelerate up, but the X axis has a small, short one typically.