DIY 4th Axis Rotary Table

[Cartierusm]

I'm going to put together my own 4th Axis for my BP CNC and was wondering if anyone had experience doing this using a rotary table?

Is this feesable? What should I look for, just backlash in the turning mechanism? Any suggestions on which rotary table to buy? Thanks.

The problem I see right now is that most places don't stock this sort of stuff even harbor freight and I would want to test it out first, for the backlash before trying.

[Bubba]

I used my phase II RT to make it CNC. I found the backlash was quite adjustible and I could take most of it out. I still make the table run in one direction just to be sure. My use is more for indexing to drill holes etc and therefore use it only in the vertical orientation. The main reason I used this one is I bought it back before I could even spell CNC much less know what it was. It has worked very well for me.

[Cartierusm]

Thanks, the Phase II are a little more than I wanted to spend. But as I'm doing more research I realized what you said that most have some sort of backlash adjustment.

[Cartierusm]

I was thinking about it, why do I need to use a rotary table and deal with all the backlash problems I'll have to address.

I just ordered a Keling 576 oz/in. Stepper motor for the conversion and I was thinking what if I didn't use a rotary table and just use this

http://littlemachineshop.com/product...2299&category=

It's a small lathe head assembly. It's accurate all I would have to do is put on a 2" gear pulley on the stepper and a 5" or bigger gear pulley on the spindle. I think the amount of power from that arrangement would work nicely.

Any comments, do you think this will work?

[Bubba]

If your going to use it as an "indexer", it would be fine. Depending on power required it might work for other uses also.

[Cartierusm]

I would be using it for doing engraving and cutting pattern with my CNC Bridgeport. Do you think that'll work or not enough holding power between the stepper and a gearbelt?

[hoss2006]

The motor and ratio you've mentioned would work fine for light duty milling up to a few inches OD.
I've done some engraving with a 495 and it held strong.
A larger ratio would be even better though.
I've used my 4th axis mostly for making timing pulleys.
It also works great as a lathe too.
Hoss

[Cartierusm]

I went ahead and ordered a 4" rotary table from Grizzyly. I have a lot of their tools and trust them plus it says it has backlash adjustment. I have a new stepper driver and a 576 oz/in. stepper coming, oh plus I ordered a tailstock. So it should work well.

Question I have an extra 4" 3 Jaw chuck and the rotary table is 4" am I going to have a problem mounting it? Any suggestions?

HOSS, BTW for years loved your website you have truely given back to the community, thanks. Question for you what do you use to program your 4th axis stuff, like engraving?

[hoss2006]

Originally Posted by Cartierusm I went ahead and ordered a 4" rotary table from Grizzyly. I have a lot of their tools and trust them plus it says it has backlash adjustment. I have a new stepper driver and a 576 oz/in. stepper coming, oh plus I ordered a tailstock. So it should work well. Question I have an extra 4" 3 Jaw chuck and the rotary table is 4" am I going to have a problem mounting it? Any suggestions? HOSS, BTW for years loved your website you have truely given back to the community, thanks. Question for you what do you use to program your 4th axis stuff, like engraving?

I don't have a CAM program with 4th axis capabilities so I cheated for the engraving.
I used Deskengrave to make the code then opened the program in notepad.
Used "replace all" to change all the Y's to A's.
I used the same technique for this job just took a lot more "replacing"
Hoss

[Cartierusm]

Cool, actually I caught Grizzly this morning before processing and canceled the order. I realized the tailstock I ordered was not the correct one, then I got to more thinking and decided to just buy the same head and spindle like on my HF 9x20 lathe. That way everything is interchangeable and if needs be I can just unscrew the chuck from the spindle on the lathe and transfer it over to the Bridgeport CNC. I'll use my new 570 oz/in. Stepper to drive it with reduction and a gearbelt.