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Author Topic: Lathe CNC conversion 1334  (Read 2139 times)

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Offline croy

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Lathe CNC conversion 1334
« on: August 29, 2012, 03:29:55 PM »
Hi,

I have a Standard Modern 1334 and am interested in converting to CNC, has anyone undertaken converting a similar sized lathe, if so any advice on motors, drivers, controllers, ballscrews, etc, will be appreciated

Thanks
Roy
Re: Lathe CNC conversion 1334
« Reply #1 on: August 30, 2012, 03:59:42 PM »
I'd go to cnczone.com and take a look at lathe conversions there, there's a lot of well documented conversions there.

I used those examples to design the brackets for my 12" Clausing 5914, I liked a retro-fit there where the guy used the original lead screws which made it real easy to switch between manual and CNC modes, I need this as sometimes I need to make quick and dirty parts and the CNC parts I need to make are pretty simple so I can live without zero backlash lead screws.

However I'm making an acetal based non-zero backlash lead screw for the cross-slide screw and so far that's working out well.

If interested take a look at:

Its reallly cheap and pretty easy way to make a zero backlash leadscrew in very limited space, I could't fit a ballscrew nut in that stock location:

http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-leadscrew-nuts-the-easy-way/page15?highlight=acetal

Paul T.
www.springtest.com

Offline croy

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Re: Lathe CNC conversion 1334
« Reply #2 on: August 30, 2012, 04:05:13 PM »
Hi Paul,

thanks for the advice. i like the way you made your leadscrew nut. very good.
Re: Lathe CNC conversion 1334
« Reply #3 on: August 30, 2012, 04:16:20 PM »
I meant to add a little more on motor sizes.

For the cross screw I wanted a motor that wasn't too big so it wouldn't be too much in the way for manual use, I made a motor bracket that clamps on the cross screw bearing housing just behind the handle. The stock handle is still in the same place but the graduated dial got replaced by a timing belt pulley for the motor drive.

However I put graduated marks on this pulley so that for manual work I still have it as a reference.

The bracket is slotted for the motor so it only takes about 20 seconds to slack the drive belt so I can use the cross slide manually.

I used the larger 400 oz-in size 23 motor that is sold on Geckodrive.com for this, its a nice combination of pretty good power in a limited size. I geared it at 2:1.

For the Z I used a 1300 oz-in size 34 motor that AutomationDirect.com sells, their STP-MTRH-34127. I liked this motor as it has a low inductance for its size, I wanted this so I could run both motors on a 48 volt supply.

Both these motors will work well with GeckoDrive stepper drivers, I'm using the G201x ones.

I need to make some steel parts that need heavy drilling so that's why I went with a pretty strong motor on the Z (lead) screw, fortunately I don't need much power on the cross-slide so the smaller motor works fine.

The Z drive uses the threading nuts on the lead screw, which means its also very quick to release those nuts so I can use feed handle on the carriage for manual work.

I used needle bearing based thrust washers (McMaster.com) to get rid of all the end to end slop in the leadscrew itself and the threading nuts on machine were never used much so the backlash on Z is actually not too bad even just with this stock lead screw, its fine for the work I need to do.

Paul T.
www.springtest.com