6" harbor freight rotary table.

[diyengineer]

http://www.harborfreight.com/cpi/cta...emnumber=47824


Could i use this with a stepper attached for a 4th axis strapped to my table?

[Jesse B]

I don't see why not.

[FandZ]

I think you'd have to look into the backlash on the unit. I've read some about them and while they are very precise in going one direction, sometimes when you try to go the other direction there's a good bit of backlash till all the gears and worm gears hookup. I don't know if it applies to this unit. I know I've seen people rebuild them to get rid of backlash and use them as a 4th axis.

[diyengineer]

Thanks for the tip!

[CarveOne]

I will agree with FandZ's assessment. I have one of the 8" versions from HF and it has a worm gear drive that is more or less filled with heavy grease. As far as I can tell, mine has no adjustment for gear mesh. It has significant backlash when reversing directions.

I have another one from HF that I've never used, a 4" 47052 model. It is much better, but it still has 6 degrees of backlash according to the crank handle dial. It doesn't show up on a part number search now.

CarveOne

[diyengineer]

So if i were to hook a motor up to it and just run it in one direction instead of backwards i would be fine? Any way to fix the backlash problem?

[Jesse B]

Originally Posted by diyengineer So if i were to hook a motor up to it and just run it in one direction instead of backwards i would be fine? Any way to fix the backlash problem?

In theory, yes; the backlash comes when changing directions, so only running it in one direction *could* eliminate all of the backlash.

On fixing it, it's pretty difficult. The gear(s) and worm screw can't have their mesh adjusted, and the teeth may just be machined different enough to have backlash no matter what you do. I'd think you'd have to replace both those things in order to remedy the problem.

[CurtisU]

I've never used it before, but how well would backlash compensation work from the controller end.

I'm guessing there's quite a bit of slop, perhaps more than what can be handled with software.

Curtis

[diyengineer]

Is there a different 4-6" unit for cheap that doesn"t possess the backlash like the others? Or is it just the nature of a cheap unit?

[FandZ]

From what I've gathered, repeatability is more important than the backlash. If the repeatability is good, then you can use software to compensate for the backlash.

If I were you, I'd suggest you contact little machine shop and ask about there smaller rotary tables. They are used to us hobbyist and would probably give you some good information.

Scroll down on this page to see their tables that are under 200. http://littlemachineshop.com/product...Product+Search

[jalessi]

Diyengineer,

Sherline makes the best small CNC fourth axis rotary "part number 3700CNC" bar none.

Jeff...

[diyengineer]

OHH nice!!! Thanks for that link!!