[Arc]

Well I've been kicking around the idea to CNC my old end mill for the longest time. Anyways On Monday I decided to get started and today being Friday I'm almost done with the hardware side. It will be driven with some Geckos and a home brew power supply. I 'm sure I'll have many questions but for now all seems to be coming together quite nice. I decided to go direct drive because it just seemed easier to me. Anyways without further delay here are some pics. If you have questions I have answers But I probably have more questions.











Well that's it for now... Im going to start working on the electronics side. :idea:

[motomitch1]

Looks good ,direct drive should be fine with stepper motors.

[Bubba]

Arc,
Looks REAL good

I wish I had thought of tapping the original nuts for use of the ballnuts, sure would have saved a lot of work fabricating new ones!

Looking forward to pictures of the rest of the project.

[dgalaxy]

Man That Looks Awsome

[Arc]

Thanks for the kind words. Yeah I figured I could sit there and fab up some new pillow blocks But I had a 15/16-16 tap lying around and it was basically a match for the Roton ball nuts. I lined up the original ones on the lathe with the original ballscrew to center it out and then went to town on it. So far so good. Now comes the electronics. This conversion has taken a total of three days. :cheers:

[ngr1]

Great Conversion! Any updates?

[eqreservoir]

Hi Arc

Please provide the part number and source for the motor to leadscrew couplings you used?

Money is a little Scarce right now. Was wondering if there was a decent way to build an anti backlash nut or buy a nut so I can use the original leadscrews until I could afford ballscrews.

Thanks.
Herman

[Jackyl]

That is a very nice setup you have so far. I just picked up a mill like this. I bought mine from MSC. It's the Rong Fu model. I've had it for a week now and I want to convert it over to cnc operation. I found a like to a place that sells a complete retrofit kit.

CNC JR Retro Kit

I'm really considering it because with the cost of the mill and the retro kit it would be under 6g coplete. I can't touch a used knee mill for that, not to mention a new unit. Everything is like 11g and up.

I look forward to seeing how your project works out. This forum has alot of information that confuses me greatly I wish that there was just a walkthrough for instalation and what parts needed to be bought to complete the conversion for these mills.

[Arc]

It Lives! Man I have been so damn busy as of late. Anyways I convinced a few buddies to stay over and we cranked it out. The system is working pretty good. Just have to set up the right scale and rackmount the power supply etc. I'll post pictures in the AM. :cheers:

[Arc]

As promised here are some more images of it in a completed state. I just also want to add a side note and say thanks to all the folks on this site. You have all inspired me to make this happen.





The rest and pretty much all the images from start to finish can be found here. RONGFU 31 If I can be of help to anyone here just ask. I myself am still learning so it works both ways. :cheers:

[ngr1]

Hello, great conversion… hope you do not mind a few questions.

Do you have the ball nuts mounted in c-channel? How are they held in?

[ngr1]

Great idea to use the original bearing blocks. Are the smaller items clutch bearings? To install the large bearings did you have to bore out the original bearing blocks?

How did you machine the ball screw ends? Any pictures of those?

Do you mind sharing the bearing part numbers?

Thanks… Norman

[Arc]

Hello, great conversion… hope you do not mind a few questions.

Do you have the ball nuts mounted in c-channel? How are they held in?

I simply drilled and tapped out for 8/32 set screws to hold the aluminum into place. I also used a threadlocker just in the event that over time the use would loosen the screws up.

[Arc]

Great idea to use the original bearing blocks. Are the smaller items clutch bearings? To install the large bearings did you have to bore out the original bearing blocks?

How did you machine the ball screw ends? Any pictures of those?

Do you mind sharing the bearing part numbers?

Thanks… Norman

Hey Norm I used the original bearing blocks without any machining done to them. I was able to find the perfect size at Mcmaster Carr. I'll throw up the part numbers in a few days. I have to find them first. I opted for the original bearing blocks because I figured that would be the easiest way. As far as the ball screw I used a Rotron 5/8 with 6TPI. I had to use my grinder and once I got it done far enough I threw it on my lathe. I suppose I have some pictures of the ballscrew somewhere. If not I know that I have a dxf drawing with the exact dimensions. I will put those up as well.

[carlnpa]

Do you use a spring/wavewasher to provide opposing tension on the ballscrew nuts to make them zero backlash?
Very nice conversion, almost elegant.

[Novah]

Hi Arc - any chance you could make some time to get the bearing info, coupling info and ball screw end drawings up on this post? I am anxious to get started on my own conversion.

How is the Z-axis working with the drive going through the fine adjustment feature? Did you have to do something to reduce backlash? What size motors did you use?

Thanks, Dave

[yukonho]

I am starting to gather parts for a similar conversion.
Keep us posted please.
Colin

[Georgie]

Hi Arc.
What size motors did you use on X and Y. Looks like Z=150 oz/inch ?

Thanks

GP

[Georgie]

What size stepper motors did you use,
Holding torque oz/inch ?
Volts amps ?
Any info would be appreciated.

Thanks

[Novah]

Has anyone figured out what Arc did with the bearings on the lead screws? I think the needle bearings are just being used as spacers to reduce the bearing bore to the cut down ball screw end.

On my machine (JET 20" swing mill drill) I have tapered roller bearings on one end of each original 19mm acme lead screw. The bearings are #30203 with dimensions of 40mm outside, 17mm inside and 13.25mm wide. My conversion uses the .631 ball screw and from Nook Industries page on machined ends, the bearing journal should be 12mm. That means the needle bearing would have to be 17mm od and 12mm id. I can't find one this size. They all seem to be 18 or 19mm on the od. I know I could machine a bushing but the convenience of buying ready made parts would be nice.

What are you guys seeing on your machines?

Is there a reason to change to angular contact bearings? Can't you zero the backlash with the tapered roller bearings? I can't see a need for end play in the cold state as there shouldn't be a lot of heat build up due to the low speeds it will turn.

Dave