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View Full Version : rotary table how do you use one



Brett Hurt
02-12-2013, 08:51 PM
i got 2 of them to day for free all most a craftsman was used and enco 8in.one is brand new . So I look on youtub and mit machine page no help, on using one where do I go or what book do I need . Like centering ect I see them used but no one talks about them.

Mike Burdick
02-12-2013, 09:17 PM
Brett,

Here's some information ...

It's for Sherline products but the concept is the same for larger machines.

http://www.sherline.com/3700inst.htm

gizmo2
02-12-2013, 10:44 PM
I'm in the same boat; I bought one last spring and just now trying to use it. First thing I had to do was make some bits for it. Some T-nuts that fit the slots, drilled and tapped for something handy. I went with 1/4-20, as I have a good assortment of bolts. Maybe your's is smaller or you work in metric, so you may need to make yours something different. Then I made a button that sits in the center. It's stepped the same common sizes as my collets, so I can center the table with whatever collet is in play. I'm not sure this is going to work as intended or not. Last, I made a sacrificial table that bolts with countersunk cap screws. It too has a small flange that centers it, and a tapped hole dead center.

I haven't had much luck yet with figuring out where the heck I am once I move off center, I don't have the digital readouts and can't seem to remember which way I've wound the backlash... But I think it'll be a powerful tool once I fix the loose nut cranking the handle.

majohnson
02-13-2013, 01:33 AM
They have lots of uses from making a simple radius to more precision operations like boring. Add dividing plates and you can cut flats on round stock to make bolts or complex items like gear. A good source for info on youTube is Mr Pete 222 he also goes by tublacane, he has in excess of 200 videos.

uncle pete
02-13-2013, 02:02 AM
I'm certainly not trying to be ignorant. But try a Google search. I got over 3 million hits on "How to use a rotary table". This forum isn't the only source of information around. But a few tips anyway.

Some of this you may or may not know. But I don't have a friggen clue what you do or don't know. So bear with me.

Like all machining, you need to know exactly where you are before you can start. That's your reference base line. So the easiest is being centered on the table or center hole. Depending on your level of accuracy needed? That table center or center hole center may and probably isn't exactly the center of the tables center of rotation. By that I mean there's going to be a greater or lesser amount of runout depending on the quality of what you bought for a R/T. So your first step is to record just what those runouts are and exactly where they occur and what the reading for degrees is on both the table O.D. and the center I.D. Those readings would go in your shop notebook that everyone should start and keep for anything that pertains to your equipment. I'd also add a red felt tip marker point at the high point of that runout directly on the table as a reminder of where it is.

OK, Due to the differences in Z axis height while setting up and then machining, this is again where the round column mills fail. But you need to center the R/T directly under the center of rotation for your mills spindle. Again depending on your needs, you may want to factor in the real center of rotation on the table by referring back to those previous measurements you recorded. But You center the R/T by swinging a dial indicator or dial test indicator in the mills spindle and either check the R/T's table O.D. or the center hole I.D. using a DTI. You correct by using the X and Y axis table movements. As a final check you lock both table axis's and your indicator should or will read zero. Once that's done, you now know where you are. Zero / zero for the spindle and table center. This gives you both X and Y axis that are centered or zeroed on the table. You then zero each handwheel dial on your mill.

Now you can fixture your work to the table. That work needs to have something you can again use to correctly align the work by either swinging an indicator in the mills spindle, or by rotating the table drive till you see a zero deflection on the indicators needle with it on the work. I prefer rotating the R/T. That centers the work to your R/T's and spindle center. Now your spindle centerline, R/T centerline, and work centerline all agree. Some work can also be done without centering the table to the spindle and just centering the work to the table rotation, and then using something like an edgefinder to locate you spindle C/L to the work.

Now you can move or offset using one table axis the required amount to say drill a series of holes evenly divided around your work. That's called the Pitch Circle Diameter. (PCD) And you do your offset by using either the handwheel divisions, an indicator, or DRO if you've got one.

For work with the R/T standing vertical and say drilling or endmilling down into the work. Then you center your work piece to the table rotation, then use edgefinders etc to locate the spindle against the work, then do an offset move. The secret is to never move more than one axis on your mill table at a time, otherwise you'll get lost and maybe have to start over. And if your not moving the table, then both X and Y are kept locked. You should also know just how much those table locks move the table over as there applied. Another item for that Shop Notebook. Even the R/T table locks may move it's table when they get applied. You have to test to know for sure.

As far as remembering the direction to turn the R/T's handwheel? Slap a piece of masking tape on the mill table or even the R/T's handwheel with a simple pen marked directional arrow.

Obviously this is just a very simple version of what a R/T is really capable of. I'd suggest you go very very slow the first few times and think and understand exactly what your doing at each step. It gets a lot quicker once you do fully understand what your doing later. But again, you do need to fully understand the basics.

Normally I'd recommend a decent book for anything someone wants to understand better. But I don't know of any single book that has everything needed. It's spread throughout numerous references.

I do think that machining gets a hell of a lot easier once a person trains themselves to visulize in 3 dimentions though.

Pete

demerrill
02-13-2013, 11:28 AM
Some nicely illustrated discussions on Bob Warfield's site: http://www.cnccookbook.com/CCRotabToys.html

And a Google search on 'how to use rotary table': http://www.google.com/#hl=en&tbo=d&sclient=psy-ab&q=how+to+use+rotary+table&oq=how+to+use+rotary+table&gs_l=hp.3..0j0i30j0i8j0i8i30.3379.13667.0.14470.23 .16.0.7.7.0.83.948.16.16.0.les%3B..0.0...1c.1.2.hp .wWNKJuR3B8w&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.42261806,d.eWU&fp=5dc6b6d2eb1a13aa&biw=1299&bih=1067

David Merrill

catman81056
02-13-2013, 07:12 PM
I came across an 10" rotory table for $50.00 and couldn't pass it up. Always wanted one for possible projects and this one fills the bill. No major make, horizontal only. After wondering how to find the center of the table I noticed that there was a hole in the center where the 4 slots meet. So I turned down a "locating pin" with a 1/2" shank. Its a nice slip type fit, maybe .0015 undersized. I figured that would be good enough to mount the table and zero out the center.