Just a Sparky
Hot Rolled
- Joined
- May 2, 2020
- Location
- Minnesota
I messed about with the spindle in my MVN the other day. Adjusting preload and adding grease. Ended up adding too much grease. Now the bearings are churning grease and getting hot. Can't seem to find my IR thermometer at the moment but at 2000 RPM the spindle heats up to the "uncomfortable but tolerable to touch" range. Not quite "too hot to touch." No-load motor loss is 360 watts. 1k RPM is 450 watts. 2k RPM is 620 watts. 5k almost gets up to speed but trips the 15 A thermal-mag breaker protecting the branch circuit just before it gets there. Not sure if that's new or not - never tried 5k RPM until now.
Wondering if a spindle rebuild is warranted at this point, and if so, what exactly the process would look like on this machine. This is the only machine in my shop that I haven't already rebuilt from the ground up and don't already know inside and out.
...Or are these temps low enough to just "let 'er buck" and wait for the excess grease to poop itself out naturally through the spindle nose? Grease used is a calcium sulfonate No. 2 with moly. (Mobil Centaur Moly 2.) Thinner consistency than whatever was originally in there. Kicking myself for using moly in a rolling element bearing. It's all I had on hand and I didn't read up on moly in rollers until after the fact. You live and you learn. Then again, the bearings are 50 years old anyways so if I end up having to replace them a little earlier because I used moly then whoppidy-doo, you know? An excuse for fresh, new spindle bearings.
Just looking for some insight, perspective and information here.
Wondering if a spindle rebuild is warranted at this point, and if so, what exactly the process would look like on this machine. This is the only machine in my shop that I haven't already rebuilt from the ground up and don't already know inside and out.
...Or are these temps low enough to just "let 'er buck" and wait for the excess grease to poop itself out naturally through the spindle nose? Grease used is a calcium sulfonate No. 2 with moly. (Mobil Centaur Moly 2.) Thinner consistency than whatever was originally in there. Kicking myself for using moly in a rolling element bearing. It's all I had on hand and I didn't read up on moly in rollers until after the fact. You live and you learn. Then again, the bearings are 50 years old anyways so if I end up having to replace them a little earlier because I used moly then whoppidy-doo, you know? An excuse for fresh, new spindle bearings.
Just looking for some insight, perspective and information here.
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