Printable View
For the Sieg X2 mill
Does anyone have any numbers for the preload of 15 degree angular contact bearings in the spindle.
There are suggestions fro "snug" etc, I was looking for some numbers to apply , like Torque, etc?
Or what are the ways to figure this out?
The bearings I bought were from VXB and there is nothing there on preload.
https://www.vxb.com/7007C-P5-ABEC-5-...cp5-abec-5.htm
https://www.vxb.com/7206C-P5-Angular...p/7206c-p5.htm
I use the same bearing in my small lathe. According to Sieg you should hand tight them, no tool needed. If you tight them using your fingers, your play will be gone. Just to compensate for the cutting forced during milling, you need a bit more torque. Keep in mind that such a fine screw thread will put a gigantic amount of preload on the bearing. I can lift my 260 kg lathe by just using two M12 spindles and tighten the nuts by hand!
Feel how easy the spindle can be turned by hand (no gear activated) and then tighten the nut by hand. If it is harder to turn the spindle, you tightened it to strong!
After tightening the nut, let the spindle run for 15 minutes at a low (200) RPM. Then gradually increase the speed in 500 RPM steps for 5 minutes.
I made a fitting kit similar to what is described here:
https://littlemachineshop.com/images...ndle%20Kit.pdf
Tightened the tool until the bearings 'bit' and then hand tightened the spindle nut once I removed the tool.
Had no problems.
hfjbuis: thanks, the extra criteria you gave is helpful.
dazp1976: Thanks, I installed new bearings and spindle, so now I am working on the motor mount. I just wanted to get a bit more precision on the preload. I think I have enough now.