Home Brew Electro-mechanical Dividing Head?

[markba633csi]

I liked Mark F's home built dividing head and Wayne's too; I was wondering if anyone has built a stepper motor based device perhaps using a commercially available worm gear reducer like MotoVario or similar.
Are there any threads concerning a project like that? Where on the forum should I be looking?
Mark S.

 

[markba633csi]

Looks like nobody has built one- guess I'll be the first to try it..
M

 

[JimDawson]

No reason it couldn't be done. I added a stepper to my Vertex super spacer.

http://www.hobby-machinist.com/threads/4th-axis-build.40642/

 

[markba633csi]

Yeah Jim I figure by the time I bought the worm gear set- I might as well buy the whole reducer and have bearings and a frame already made. You can even get Nema motor adapters for them too. So I could have hole plates hanging off the back or use the stepper. Have to machine some kind of collet chuck arrangement and drawbar, but that's no big deal. A simple TTL counter circuit would let you input steps, without needing a full-on CNC setup. Only thing I'm wondering about is backlash. Just a thought blowin' thru the cortex...
Mark

 

[JimDawson]

If you built your own gearbox, you could put the worm shaft on a cam so as you rotate the cam, it would engage more or less with the worm. That way you can adjust it for zero lash, or rotate it out of engagement and allow the main shaft to freewheel.

 

[rwm]

Interesting idea. Can't wait to see...
R

 

[rgray]

This is my Harold Hall / Snailworks dividing head. Started out as a Harold Hall indexer using gear teeth to index. Then followed the Snailworks build for an Arduino indexer and adapted that to it. http://www.liming.org/millindex/
It's realy nice compared to counting holes on a dividing head.
I used a worm set from a honda car window motor....kinda cheesy but works ok not much backlash and I still used the lock to lock the spindle after it is to location.I've been going to update it to an anti backlash worm gear might get to that someday. Then the lock would probably not be needed as the large stepper has a lot of holding power.

 

[markba633csi]

That's the idea, nice build - is that a Diamond mill I see in the pic? That table sure looks familiar...
Mark S.

 

[rgray]

Near as I can figure it may be a Sheldon /Vernon. I don't find any manufacturer name , stamp or tag on it so I'm not sure.