6" Rotary Table

[Bob La Londe]

I am looking at the 6inch rotary table to go on the 1100S3. Who already has one? What is the backlash like? Can you adjust it out like regular rotary tables? If so how much and still have good movement?

I've got some parts coming up that would ideally be turned on a CNC lathe. In the past I manually indexed them between two spindexers face to face, 3D machined them one side at a time, and finished the registration surface and polished them on the manual 1440 lathe. I'd like to better semi-automate the process. I have a bunch of them to cut this time around. The customer liked the prototype run. I don't have an issue with manual finishing, but if I could do less of it and get to that stage faster it would be great. I think I could reduce it to mostly a 2D profiling operation with proper 4th axis setup. Just some emery polishing and a facing cut on the lathe. Rgidity of the part itself might preclude an actual finish quality pass on the mill, but I'd sure give it a try once or twice to see.

I did look at the MiniArc, but its out of stock, and I don't see this as being a permanent installation on the table. It will "probably" get used a coupe times a year for a batch job and then set on a shelf. Yes I am aware that once I have it sitting there I will probably take on more jobs that would use it.

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[spyderguy550]

Bob --

If by MiniArc you mean the Tormach microARC 4" 4th axis, the website shows it as in stock. I have no first hand experience with it but from what I've read it has close to zero backlash due to its use of a harmonic drive.

[Bob La Londe]

Yeah, I must have looked at the wrong thing or it was back in stock. I had already ordered the 6 " rotary by the time I saw that. I was able to find an old video showing how to adjust the 6" rotary that seemed to indicate I could adjust to about 60 arc seconds reasonably and still get intended performance.

[fi man]

Hi Bob,

How do you like your 6" cnc rotary table from Tormach?

Can you change directions and not get lost from backlash?

Cheers,

FI

[Bob La Londe]

Its still in the crate. At any given time I have 2-6 months of prepaid work backed up. I haven't gotten to the job I need it for yet. I expected backing up would be more a factor of how accurate the part needs to be and how big the part is. There are ways to address it of course. The easiest one is to add a bit of code that allows you to backup past your destination, and then move forward again before resuming cutting. Like many things accuracy can be as much a factor of the machinist as the machine. As is also the case many of those things are easier for an experienced machinist/programmer/machine operator to deal with than for somebody who is still struggling up the initial steep learning curve. In some areas I am both experienced and inexperienced. We shall see how well it goes. LOL.

I probably should have waited for the harmonic drive, but I can make the RoTab do the job. I've made these parts in the past simple from manually indexing a pair of spindexers mounted face to face. The 4th axis powered rotab should just allow me to make the parts with less user intervention and perhaps a little less time per part. Once I have the rotab figured out and setup for the PCNC1100 I intend to also setup a driver on one of the little Speedmasters to use it there when using tiny cutters at high rpm.