Rotary table

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mf294-4

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Need a vertical rotary table with index capabilities. Looking at the Grizzly T25937. Anyone use this or have any alternate sujjestions. Just a home shop not used very often.
 
I like my little 6" grizzly vertical horizontal rotary table. It has dividing capability and plates came with it. That's not exactly indexing though. Not as fast and easy as indexing. I settled on it as the solution to as many shop problems as I could squeeze into one tool. I think quick indexing is the biggest compromise made by going that route.
 
I am curious as to the difference between using dividing plates on a rotary table versus "indexing". Would you care to elaborate? I am also considering a RT in the near future... tx!
 
My take on it is indexing like with a spindex is all done simply with holes and a pin and achieves 1deg accuracy where rotary tables with plates achieve minute and second accuracy. A spindex is a very cheap handy tool for simple quick work if you are not doing large complicated work and only need 1deg accuracy.
 
It's all indexing, just different types.

A series of holes or notches around a rotatable fixture is called "direct indexing". A handle geared to the rotating fixture with a plate with holes in or similar is "simple indexing". Lots of dividing heads have direct indexing options - quite often 24 divisions - as well as the geared handle and plates for simple indexing.
 
The difference in accuracy is all in favor of the geared dividing head. On mine, there is a 40 to 1 gear reduction, so any error because of pin placement is reduced by the same factor of 40. The spin indexer, you get whatever pin error or slop exists coupled directly into your part.

I have both a spin indexer and a dividing head. I made a tilt table, first with the indexer to cut reference flats, but I was not satisfied with the result and had to recut with the dividing head, which came out spot on, measured against angle gauges and dial indicator.
 
There seems to be some confusion over the distinction between resolution and accuracy. Resolution is the finest increment that you are able to resolve. i.e., a spin indexer with 360 discrete positions has a one degree resolution. There is no way that you can set a 15.5º angle. However, a 15º angle would be 15º +/-4' (.07º) from the Shars spin indexer specification.

The biggest difference between an indexer and a rotary table is that the rotary table allows moving to any angle within the limits of the RT resolution. An indexer has to work with the available divisions. It works well in making bolt circles with a set number of holes. You cannot set a 13º57'23" angle with it

OTOH, my RT has a 90:1 gearing and is able to resolve 5" (.0013º). If I wanted to make a 127 tooth gear with the RT, I could by incrementing my position by 2º50'5". (To minimize errors and prevent error stacking, I would use an Excel spreadsheet to calculate the settings). It would be more cumbersome than using an indexer but it will get the job done.

In an ideal world, I would have both but faced with the choice of an indexer or an RT, my choice would be the RT, simply because it is more versatile.
 
If one has a universal dividing head, where the spindle is geared back to the dividing plate through change gears, prime numbers such as 127 can be divided exactly with no stacking errors or spreadsheets, this I did to make metric transposing gears for my lathe and automatic gear cutter.
 
benmychree said:
If one has a universal dividing head, where the spindle is geared back to the dividing plate through change gears, prime numbers such as 127 can be divided exactly with no stacking errors or spreadsheets, this I did to make metric transposing gears for my lathe and automatic gear cutter.
Click to expand...
That is so complicated, I put that procedure right up there with rocket science.
 
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