My new (old) lathe almost complete

[DAlgie]

Thought I'd post a couple of pics of my lathe as it is, most of everything is done and working, just now need to machine all the turret toolchanger parts, the wiring and everything is ready for it to bolt on. This lathe uses a 400oz/in stepper driving the X axis through a 2:1 reduction belt, plenty of power there. The Z axis is a 1200oz/in direct drive, it's marginal in power but I still have some drag to deal with yet. Both ballscrews are 5 turns per inch. Uses Gecko 201 drives, 34 volt power supply from a 500VA torodial transformer, PDMX 50 volt AC/DC converter- power conditioner, Cambell breakout board, huge fan cooled gecko heatsinks. Stainless sliding half cover for coolant and chip control makes it really nice and cleanup easy. Computer/ worktable cart is an old Indy car shock dyno cart that was perfect for this use. I still can't believe how much equipment, gears, feedscrews, front apron, threading gearbox and assorted crap I had to ditch off that wasn't needed anymore, you'd think that the ballscrews, steppers and electronics would't be much more, if any, money to manufacture and add for a low cost commercial CNC lathe. And without all that mechanical stuff the thing runs so much quieter now! Been a really fun project but I need to get back on the aircraft stuff...
    Dave.

[fdos]

So funny seeing your lathe, it's obviously the same as my Warco1340 which is a taiwanese copy of an English  Harrison M300.   I've had mine years, no intention of converting it though, already got CNC lathes.

Conversion looks tidy though, Have you not converted to ballscrews?  That would seriously help.

Wayne....

[DAlgie]

Yes, both are ballscrews, this is a chinese lathe, still made and sold by different companies, this one was from MSC, actually quite a nice lathe as it was.

[ynneb]

Youve done well. Show us some pictures of stuff you have made with it.

[DAlgie]

Make stuff? I need to get the spindle index sensor to read right yet, still running in the 4 or 5 hundred thousand rpm range, not at 500 as it should be, so the feed per revolution is a problem and I don't have the confidence with it like that, still need to pay you guys for all your work with the software too...

[fdos]

Whats up with the speed sensor?

I've also had some issues with a speed sensor on my VMC, I chose to make my own, it works ok, but have found some issues with stepper drive noise screwing low speed readings.  Like 40,000 ish when it should be in the 100's.  I'll probably end up making my speed sensor work at 24v levels like the rest of the machine.   TTL levels are so prone to noise issues it pays to do it the way the machine was designed.

You dont HAVE to use feed per rev.   I often just use feed per min on my lathes.

Obviously it will have to work right for screwcutting.

[DAlgie]

Yeah, it's starting to annoy me a bit, I ran a seperate shielded cable, grounded one end, even ran a shielded cable inside the controller box, and no luck. Wierd though, it sometime works for a short time, exactly right, then goes crazy again, wondered if it's not just noise. Like you say, maybe the best thing is to convert it up to a higher level, low level signal stuff gets noise so easily it seems. But I don't know how to do that.

[fdos]

What are you using for a sensor?

To convert I've jut used opto couplers witht the correct current limiting resistor for 24v..   All my limits,homes, etc are 24v already.

[DAlgie]

I used the PDMX spindle sensor at http://www.pmdx.com/SpindleSensors/index.html it uses 5 volts, and is an optical. Found out now, the problem seems to be coming from the sensor itself, no amount of grounded shielding changes it a bit, messed with the index debounce, still no change. If I pull the sensor off the lathe, it goes to zero, if I put anything in the sensor gap, it goes crazy, metallic, shiny, dull, it sends it through the roof, seems like it's got problems of it's own, there is a correct 5 volts to it, and a decent ground back to the parallel port board, and the signal line is shielded, as I said. I'll contact PDMX and find out more there i think.

[Ron111]

I'm also looking at using the PMDX optical spindle sensor.  Did you get the problem resolved with the sensor or what did you choose to do.  I appreciate your input.

Thanks Ron