Rotary table gear cutting

[Hukshawn]

How difficult is it to cut gears on a rotary table and not a dividing head? Is the math easy enough to figure out? I need to make a bunch of gears for my mill quill power feed and I can't afford a dividing head. So, I'm looking at rotary tables for Christmas.

 

[Asm109]

The math is simple. Advancing the exact same amount for each tooth, not so much.
Angle per tooth= 360/number of teeth.
If that ratio works out to an even number of degrees, celebrate and make the gear.
Need 23 teeth? Angle= 360/23= 15.652 degrees
Gotta keep track of those partial degrees and add them up and move the dial accurately. One mistake in your math or turning the knob and you have scrap.
The more teeth, the more opportunities to Biff the job.

 

[DAT510]

My Vertex RT came with dividing plates. With a 90 to 1 worm gear ratio, it has most of the capabilities of a dividing head, if not all.

 

[British Steel]

There are add-on plates and sector arms available for the vertex tables that will let you do most tooth counts up to 270 pretty easily, but not some Useful Primes, like 127 for metric conversions... Not that cheap, but not that difficult to make your own with care and time.
The maths is simple with the plates, multiply the number of holes in the plate circle by the worm ratio, divide by the desired number of teeth to find how many spaces to advance for each cut, if it doesn't come out to a whole number pick another hole circle and repeat - simples

The sector arms are set with the number of spaces between them and rotated each cut to guide you to the next - also simples

Dave H. (the other one)

 

[brino]

I made a small rack once using the y-feed of the mill for cutting the teeth/gaps.
I was afraid of messing up the dial numbers, especially with the "roll-over" of the dial at 0.250".
I did the math in an excel spreadsheet first.
I printed it out and kept it with me at the mill crossing off each line as I went along.
It worked out well.
-brino

 

[Hukshawn]

Well this is great. I can get a 6" rotary table with dividing plates for 300 off Amazon. And I put a boring head on that same wishlist for Christmas.
I feel I can take care of most of the gear necessities for my mill quill power feed with this. Most are brass, there's some powdered metal gears stacked in a group with broken teeth in the speed selector, I may have to buy those gears.