I am building a 4 axis mill for turning wood columns 24" by 12'. X, Y and Z are up and running. Ready to start on A and realize I have a MAJOR design flaw. I need to be able to cut both directions on the Y axis and 1 degree of backlash on the A axis equals .2" on a 12" radius. I am thinking that using a 60:1 or higher worm gear with one idler loaded against the CW face and another loaded against the CCW face of the driven gear may solve my problem. This would drop my max RPM below 10 and I would like about 50 RPM. Any sugestions?