Jet 1640 bearings getting hot

[john patrick]

I'm finding that the front bearings on my 4 year old Jet 1640 are getting almost hot after lengthy use at spindle speeds. For example, after 10-15 minutes at 2000 rpm. the bearing housing is almost too hot to touch. Plus neither the manual or the web seems to have instructions on how to change these bearings. If anyone can shed some light on a source about changing these bearings, I would sure appreciate it. thanks,
john p

[John Keeton]

See if this helps - https://www.youtube.com/channel/UCdF...7HDJ4U5XoxFH7g

it was posted in a thread seeking help on changing bearings on the Jet 1642 and should be very similar.

[John Keeton]

Also, see this thread - https://sawmillcreek.org/showthread....nt-on-Jet-1642

[Reed Gray]

My lathes run coolest when I am sanding because I sand at slow speeds, like 50 rpm and slower. They run warmest when I turn bowls because I really make them work hard. I have an old Delta 13 inch heavy planer. I was running a bunch of oak through it and it got hot enough that it was like your situation, almost uncomfortable. I was told this is common for them. If you can smell anything, then it is too hot. I have burned out a couple of motors on other tools and there is a specific electrical burn out smell..... If you are hearing bearing noises, then that indicates a problem as well. The motors are always warm after a turning session.

robo hippy

[Richard Coers]

Heat is rarely the first indicator of worn out bearings. Noise is the #1 indicator. Heat may indicate too tight of preload and when the shaft starts to warm up it expands and loads the bearings even more. I have no idea on how those bearings are mounted, but look for some videos and see if you can run a little less preload. Final thought is that almost hot may be acceptable. The motor on my little Jet mini lathe got too hot to touch, but never failed. Get a laser thermometer and gather some data before just randomly changing good bearings.

[Kyle Iwamoto]

The motor on my little Jet mini lathe got too hot to touch, but never failed. Get a laser thermometer and gather some data before just randomly changing good bearings.

My Jet mini motor is the same, the bearings gets hot when I turn for long times at high speeds. My 1642, I have never checked if the bearings get hot. That motor gets quite warm also. I've been told that TEFC motors do run a bit warm.
As mentioned, heat is usually not an indicator of a bearing failure. Noise and play are.

[John K Jordan]

... Get a laser thermometer and gather some data before just randomly changing good bearings.

How do you measure temperature with a laser? Or do you mean an infrared thermometer with laser targeting?

Some have two lasers with beams angled to show you the approximate edges of the spot being measured. I had a good Fluke for about 8 years, hate to be without it. A thermocouple reader is another nice thing to have on hand, complements the IR instrument.

[Russell Neyman]

The 14 and 16-inch Jets have a spring washer that allows minimal runout (the east-west movement) so the bearings don't get stressed. I'd check to see if the nut at the handcrank end of the quill is too tight.

[John K Jordan]

The 14 and 16-inch Jets have a spring washer that allows minimal runout (the east-west movement) so the bearings don't get stressed. I'd check to see if the nut at the handcrank end of the quill is too tight.

Also, too much tailstock pressure can stress headstock bearings.