Large A axis (rotation) control HELP!!

[Art Ransom]

I am building a 4 axis mill with 24" A axis to make wooden columns. I want the ability to carve on the columns but that creates motion control problems. ie backlash. Best idea so far is using 24" gear on A axis and 1" gear on stepper either planatery or worm. Surely someone has a better idea.

[Al_The_Man]

There is not a great deal of choice if you want accurate reduction, if you are looking at 24:1 Then I would source a planetary gearbox off ebay, They are compact, low backlash and high ratio's.
Bayside and Alpha are a couple of good makes.
Al.

[RICHARD ZASTROW]

ART RANSOM, How about a double reduction timing belt drive? Keep the belt tension tight, use good radial bearings. Place a bearing outboard of the driving motor to keep from overloading it's bearings radially. I've used this method on machines requiring very accurate timing/indexing.