Perry Harrington
Titanium
- Joined
- Oct 7, 2006
- Location
- Klamath Falls, Oregon
I'm thinking about reballing the screws in my mill in the near future and I wanted to go about it sensibly, only needing to order 2 or so sizes of balls.
I've read that ballscrews have a gothic arch profile ground into them, which makes sense to avoid skidding. However, this places the majority of the load on a small surface area, which is likely the major component of the wear.
Getting new, or having the screws professionally serviced is out of the question. The X screw is about 53 inches long and 1-3/16 in diameter, with a 4 or 5 pitch.
I seem to recall reading that you can calculate the precise ball size needed based on the pitch diameter and the measured backlash. I could model this simply in a CAD program, however the gothic arch ogive data is the gotcha I don't have.
Does anyone have a formula or spreadsheet for calculating the ball size? I got lucky on my last screw and guessed right, but it had much less backlash.
At 18 cents per ball, I'd like to try and contain my costs as much as possible. As it is, I'm probably going to spend over $2k in parts to repair and upgrade this mill (a Shizuoka AN-S).
I've read that ballscrews have a gothic arch profile ground into them, which makes sense to avoid skidding. However, this places the majority of the load on a small surface area, which is likely the major component of the wear.
Getting new, or having the screws professionally serviced is out of the question. The X screw is about 53 inches long and 1-3/16 in diameter, with a 4 or 5 pitch.
I seem to recall reading that you can calculate the precise ball size needed based on the pitch diameter and the measured backlash. I could model this simply in a CAD program, however the gothic arch ogive data is the gotcha I don't have.
Does anyone have a formula or spreadsheet for calculating the ball size? I got lucky on my last screw and guessed right, but it had much less backlash.
At 18 cents per ball, I'd like to try and contain my costs as much as possible. As it is, I'm probably going to spend over $2k in parts to repair and upgrade this mill (a Shizuoka AN-S).