Check the rotab can be mounted on its side or you have a big enough angle plate. Sometimes the extra diameter of the rotab gets in the way but otherwise it is just as capable as a dividing head until you get to the more complex 'universal' type that can tilt and do differential indexing for prime numbers, or be driven to make spirals.

Unless you have a CNC machine or stepper driven rotary table, a manual rotary table is one of the few ways to machine cylindrical paths in a way you couldn't otherwise. You'd struggle to do that with a dividing head. I used my rotab to machine internal and external surfaces with success, although nowadays my CNC machine does a much better job in a fraction of the time.

Murray

Dividing head

better for gear cutting and cutting splined shafts.

will give you angles assuming your machine is big enough.

Rotary table

Best used flat so good for drilling circle plates

some will mill curves if the gear and worm are up to it and some will strip the threads.

OK for any dividing that does not need a tailstock suport

I use my Rotary Table in both Horizontal and Vertical mode, which includes cutting gears.

But, as said, BEWARE of errors in the division tables supplied with the table.

My Vertex HV6 is one such. It cost me three scrap items, before realising that the errors were not mine. I made up my own division table, using EXCEL. This showed that the published table had eight errors or omissions!

If you have any doubts about the division tables, take time out and calculate. It may be time well spent!

Howard

How long is a piece of string?

I have happily cut curves in mild steel and gauge plate on my Soba 6" but they were within a reasonable expectation of what the table could handle and the depth of cut was also appropriate to my machine and tooling. Take a look back through some of Paul's other photos and see the size of work being done on his similarly made but "quality labled" table and is it any wonder the gears stripped?

I've been using the 6" one from ARC recently and that is quite nice to use as well, not sure if the gears on that are iron or steel.

Apologies to Howard if this is well covered elsewhere, but the calcualation to *check* an entry in a division table is relatively simple. It does involve vulgar fractions. Do schools still teach that?

An example I found is that for a 90:1 reduction and 13 divisions you require 6 and 36/39 turns per tooth.

(Turns * Divisions) = Reduction (teeth on worm wheel). Those need to match exactly. All integers, No tolerance. No rounding.

13 divisions * 6 whole turns = 78. For the partial turns: 13 * (36/39) = 12. 78 + 12 = 90.

Without wishing to be rude, it must take some effort to damage the worm and wheel, unless the design spec calls for putty or plasticene!

If anyone wants to try amending the original spreadsheet for gear ratios other than the original 90:1, the EXCEL spreadsheet is viewable at the top of the thread quoted by Neil. Hopefully, changing the formula from 90:1 to, say, 40:1 will produce sensible answers for Rotary Table or Dividing head with that ratio.

Am wondering if I am clever or brave enough to make two more division plates for my HV6. A "D" plate with 22, 24, 26, 28, 32,34, 38 holes and an "E" plate with 42 and 46 holes. All these should be "doable" with the existing "A", "B" and "C" plates, and would fill a few gaps in the table.

Whether or not I would ever use them, is another matter, but "They would come in handy, one day".

Another project would be to make a small Dividing Head for the mini lathe, (inspired by Stub Mandrel's one, using the division plates from the HV6. Another "Make it up as you go along job"!

Should prevent me getting bored, but not frustrated!

Howard