Are end supports required on the Y and Z axis of these bench top mills ball screws?
I've noticed everyone supports the end of the ballscrew on the X but haven't seen shots of any supports on Y or Z.
Not sure if I need to design one in on my conversion.
My Sieg X3 does not have a support on the Y. On my Z the end just rides in a bushing that was there from the old acme lead screw. As l long as the other end is held in angular contact bearing to prevent axial movement and the screw isn't whipping around when the nut is near the supported end you should be good.
Longer answer - the maximum rotational velocity of ballscrews, and thus the maximum linear speed of the axis is massively increased when both ends are supported, as is the load handling.
The ballscrew specifications can tell you what that is for a given length for the common mounting options. Most bench top mills have relatively short unsupported ballscrews, so a single fixed end mounting can usually provide as much speed as the spindle can handle.
For example, the Light Machines Benchman XT has 16mm diameter 0.2" pitch ballscrews that with the single mounting are good to about 300ipm feed rate. The longest travel is about 12", and maximum feed rate 200ipm. It's about as much as the servos and 2hp spindle can handle. Get much beyond that, and it would need more mass and rigidity to handle the loads anyway, and then it wouldn't be a bench top machine any more.
If in doubt, pull the specs on the ballscrews. The math of that part isn't difficult.
Y and Z ballscrew end supports
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