7x12 Mini Lathe CNC conversion

Jfong

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After converting a unimat lathe to cnc for my buddy, I decided that my own 7x12 mini lathe needs to be converted too. I had this short thk kr26 linear stage that I got for about $40 on eBay. To small for anything else but perfect for the lathe cross slide X axis. The carriage Z axis is a 10mm diameter THK ground ballscrew purchased from eBay for $115. Stepper motors are 300oz-in nema 23 that was given to me. Stepper drivers are Gecko210 also purchased used from eBay for cheap. Power supply is a diy 36 volt output from a transformer salvaged from a old broken desk lamp.

Backlash on both axis is minimal due to the high grade THK ground ballscrews. Rapid speed is set at 100ipm. I had tested it at 200ipm but thought that was ridiculously fast for such a small lathe.

Mach3 Turn running on a old P4 desktop using parallel port step/direction output.

In the video roughing pass is at 5ipm and the finished pass is 1ipm.

http://youtu.be/zuGZxvZJS_w


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Nice...! Did you consider the third axis for threading? Is this something you will add later on?
 
Nice...! Did you consider the third axis for threading? Is this something you will add later on?

Thanks!!!

I haven't added the spindle encoder to the headstock yet if that is what you mean. Mach3 requires that so it can read the rpm of the spindle so it can do synchronize threading. I've seen some threading youtube videos and it seems to work very well.
 
Thanks!!!

I haven't added the spindle encoder to the headstock yet if that is what you mean. Mach3 requires that so it can read the rpm of the spindle so it can do synchronize threading. I've seen some threading youtube videos and it seems to work very well.

Thanks for the reply, Yes that is what I meant, sorry if my terminology is off CNC is fairly new to me, I'd like to do what you've done some day but for my purposes the threading would be a must to justify the time and expense of such a project, but even with the 2 axis you've made radius and ball turning a lot simpler.:))
 
Funny that you should say that. I did my first ball radius turning yesterday. I just used the Mach3 wizard to create a simple round end on a piece of scrap aluminum. I was impressed lol.

The time spent to to do the conversion was less than a week working a couple hours a day. This has been my 6th cnc conversion so I'm getting better at it.
 
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Some pics of my small basement metal workshop area. The gantry cnc was built last year. The smaller x1 mill has servos on all three axes. The larger x3 mill needs the z axes ballscrew to be installed. The x and y are servos too.

There are a couple other cnc machines that I built but they are now at my brothers place.
 
Some pics of my small basement metal workshop area. The gantry cnc was built last year. The smaller x1 mill has servos on all three axes. The larger x3 mill needs the z axes ballscrew to be installed. The x and y are servos too.

Thanks for posting the pictures, nice shop and CNC machines...!:))
 
Very nice jfong, if you figure out threading could you help me out.
 
Thanks,

I have to install my hall effect sensor to the rear of the spindle this weekend. I saw your videos but unfortunately I don't know anything about threading just yet. I ordered some 60degree inserts from eBay today. Hopefully will have the lathe all setup for thread testing before they arrive.
 
Thanks,

I have to install my hall effect sensor to the rear of the spindle this weekend. I saw your videos but unfortunately I don't know anything about threading just yet. I ordered some 60degree inserts from eBay today. Hopefully will have the lathe all setup for thread testing before they arrive.

Good luck with that, please keep us posted with your progress.:))
 
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