Stepper Motor for 4" Rotary Table

[cliveastro]

Having finished my 3 axis X2 mill I thought I might add the 4th axis and use my 4" rotary table and I was wondering what size stepper to use. I do not think I need a 282 oz in as I have on my X and Y. Any thoughts on how small I can go. Many Thanks.

Clive

[cjdavis618]

I have one on my sx3 and I just used the same size. Maybe someone else will chime in that has had mixed size motors. Most I have seen are the same as the other table motors.

[jalessi]

I have several machines with 72 to 1 reduction rotarys with 80 ounce steppers.

If you have some spare steppers try them, most likely they will work fine.

Is it worth consuming ten minutes of time?

Jeff...

[Torsten]

It's all in the Transmisssion Ratio.
I asume your X and Y axes use a leadscrew then figure out the
the transmission ratio based on your screw pitch.
Like one rotation advances the table this amount.
Use the same Ratio with your Rotating Table, a 4" RT. may want to cut something at say a 5" diam. as a worst case example.
This would be equal to a rollup of 5" x Pi. (Pi=3.1415) linear distance.
Figure in your RT. gear ratio and make up the difference with Pulleys if needed.
Good Luck

[cliveastro]

Unfortunately I dont have any spare steppers to try with. Mine is a 90:1 ratio table. So a 80 ounce should eat it. However I will work the transmission ratio.
Many thanks
Clive

[LongRat]

The only reason to use a bigger motor would be to overcome the friction of the worm drive. There's potentially a lot there, if you need to mesh it tight to overcome backlash. There's a big difference here between the best and the worst tables available. I have a Vertex 4" table and I run it off a 280 oz.in motor. No problems at all. I run my axes with 425 oz.in motors.