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04-20-2017, 04:40 PM #1
Use of loctite for bearing hsg. For new install OK??
I have just repaired a import bench grinder that made odd noises and found that the 6000 series bearing was spinning in the housing. I used loctite and now it is quiet after reassembly.
I do a bit of work for someone who makes up belt sander pulleys and the used units often end up spinning the bearing in the aluminum pulley. I was shown one pulley where the bearing dropped in and rattled around it was so worn.
I suggested that all new installs should use a bearing retaining material like Locktite to eliminated the movement later on in life. The pulleys are CNC machined and are the right bearing interference but this housing wear is a regular occurrence on old machines.
Any opinion on using a retainer fluid on new installs??? I see it as a belt and suspenders approach that can't really do harm... or am I mistaken?
04-20-2017, 04:42 PM #2
It doesn't work. People think it does. I don't know why.
Bore it and press in a sleeve. That is the only correct repair.
04-20-2017, 04:50 PM #3
I would do the same.on a low end grinder.... I picked up Taiwan (I think) bench grinder at auction that runs like a precision spindle. If it was reversible I would put it on a grinder. Yes it may be.
Yes runs smooth with no wheels, with dressed wheels and has no end play. Yes would need to scrape or grind the hubs if using on a grinder.
Once saw a Baldor bench grinder mounted on top of a Cinci #2
04-20-2017, 06:41 PM #4
Are you sure the bearing wasn't supposed to slide in the housing? Most are. If it's "Spinning" that means it's messed up somehow. Supposed to be locked to the shaft and have enough internal clearance to "rotate" the inner portion only while allowing the outer to slide with thermal expansion.
Now you've stopped it moving so it will just wear out the bearings. Toss it in the garbage or sleeve and bore it correctly.
Gordon Heaton liked this post
04-21-2017, 06:22 AM #5
Lakeside is correct. Motors heat up, the rotating parts at different rates than the stationary and there must be allowance for changes in length.
The other reason to have one bearing slide a bit in its bore (in the case of two bearings on one shaft) is to allow the correct preload on both bearings, which is applied by a spring washer in the same bore as the sliding bearing. Preload keeps the balls within the bearing always in contact with the races, which helps the bearing last.
If there were no preload, the balls would likely contact the race at the bottom of the rotation (due to gravity), and since the bearing has internal clearance, not contact the race near the top. So the ball slows down at the top and speeds up again when it contacts the race near the bottom. All fine, except that the balls skid a bit when contacting the race again. And that skidding is a common failure mode for bearings.
So if one bearing is sliding, it may be designed that way. And if there's a finger type spring washer in that bore, it's definitely designed that way.
04-21-2017, 09:33 AM #6
There was fretting on the outside of the ball bearing as well as wear in the aluminum housing. ( black aluminum oxide film) it is a cheap import so as suggested next stop is the scrap bin.
Thanks for info.
04-21-2017, 09:36 AM #7
cheap import..you did good to make it run smooth..agree it may last for a day or a number of years.
04-21-2017, 09:40 AM #8
i think what he was asking was NOT about the next repair job but new units - should they be loctited before use
04-21-2017, 01:32 PM #9
I personally like loctite, it works for me and it stops my customers having down time due to fretting type wear. Parts need the right fit to benefit most though + they have to be clean.
04-23-2017, 06:23 AM #10
it will probably depend on how hot the locktite gets.