Gear and spindle temperature rise
- I recently bought a gear head drill mill. I changed out both the lower and upper spindle bearings. I monitored the bearings for temperature and after one or two adjustments I got the bearing preload with minimal spindle movement and low bearing temperature.
I have noted that the spindle gets hot. I suspected the spindle upper bearing but after rechecking find it is ok.
After running the mill at max speed (1000 RPM) without the spindle in place for about 10 minutes I find that the source of heat is the gear driving the spindle. If I put my hand up through empty quill housing I find that I the spindle drive gear is too hot to touch. The gear box also rises in temperature but is only warm to the touch from the outside. I expect some temperature rise but I don't know what is typical for the machine.
The motor appears ok and rises in temperature as much as I would expect it to.
Question - Is the hot spindle drive gear normal or is there another bearing too tight or going bad? There does not appear to have any noise associated with the mill running but I don't know the difference since it has sounded the same since I got it.
Thanks for any input.