Dimensioning and milling strategy for a rotary table

Oct 21, 2007 1 Replies

Hello all,



I am getting close to having to produce some results on a Phase II 8 inch H/V RT. Advancing the dial moves the table CW, which disappointed me for a second or two until I thought of what would be happening on the part - the angle in increasing CCW, just as I was taught to measure them. Is that the idea?



I appear to be able to use a zero set clone to zero the mill dials under the RT spindle.



I am still working out whether I will pre-square and bore a reference hole, or touch up the boundaries of the parts after clamping on the table. I am not sure exactly how to put this, but I assume that if I start with a vise setup, I will need to bump part over the RT's axis, and then indicate (moving the mill table this time) and the call that zero on the RT.



At a minimum, I would need to clean up the thickness, and suspect it would be best to that in a vise. Having done that, I could then (I think??) just slap the rough part on the RT, and start milling with the RT arbitrarily zeroed - the part's edges will get their orientation from the mill table's movement, right?



Does that make sense? Do you have a preference? They seem to be rotary analogs of things I do on my mill now. Sometimes I simply clamp something to the table, either on setup blocks away form the edges or on scrap, and then start milling. Then I find the left and right edges to zero dials, and I'm off. I mention this not to tell you guys what you already know, but to ask how to think about the same kinds of operations on the RT.



If I first bore a reference hole, how would I measure distances from it? So far, I think I would best off trusting the dials, or is there an caliper attachment I need to get to allow measuring from the hole? Any other tricks? Is there any other way to measure distances from the RT axis? With or w/o a hole there?



Re backlash on the RT: it appears to be around 20-30 seconds of arc. In short, I really have to feel around for it. I am basing that on the method I use with my mill, which is to advance to a given number, reverse until I feel resistance, and return, looking for resistance to return just as I get to the forward-moving number. It usually takes a thou or so of finesse (read cheating) to get it right. Is that reasonable?



Again, I hope this all makes some sense.



Bill


I was kind of hoping you would get some response to this Bill. I'm a bit curious about this subject myself. I've never seen one being used or read up on it yet either.

McDuffee just posted an interesting site though. I noticed this on it right off and thought you might get some help from it. See:

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