Repacking Bearings - and saving a few bucks

[damienhazo]

For those of you who don't know me, one of my hobbies aside from woodworking, is buying 2nd hand tools. The first thing I do is pull them down and take a look inside.

More often than not, it is a bearing that has caused the owner to part with it through eBay... Japanese, English and German bearings aren't cheap and most of the time they are still good - just a bit crunchy. So I thought I'd make a few pics and document how to repack them for those who want to save a few bucks: (Note: this only works for bearings with a rubber seal)

Attachment 58461
First thing to do is remove the seal. This is simple and I find it easier to lift from the inside ring outwards. Just lift enough so that the outer edge of the seal rises out of its groove.

Attachment 58462
These seals have an integrated metal strip which shouldn't be bent too much. Once the outer edge has lifted, simply take hold and removed the seal. Old grease can be seen in the inside of the seal and bearing, mixed with fine wood dust. Do the same with the other side then up into the bath for all the parts.

Attachment 58463
Give the bearing a really good washout with a cleaning agent. It should of course be something that won't attack rubber or plastic. Definately NOT ascetone. Once clean, the bearing should spin really easy. There should be no real resistance. If it crunches anywhere, wash it more thoroughly. Blow the bearing clean of any cleaning agent with an air compressor. If you don't have an air compressor, submerge and rinse the bearing in unused cleaning agent before letting it dry.

Attachment 58464
Pack the bearing with new grease. The amount is not critical because the excess (if any) will normally be thrown out through the seal after initial usage (centrifugal force through high RPMs). Too less, is of course, not a good thing. That's why I recommend a bit more if you're not sure.

Attachment 58465
Push the seals back in and give it a roll. It should move freely but not be able to free-spin. There should be no crunching or hinderance of movement. I've compared the repacked ones after 5 minutes of use (distributes and regulates the grease) to new ones and can't tell the difference...

Damien
PS. Ever wonder how a bearing is made? When the inner sleeve is inserted into the outer - and positioned so they are touching - there is enough space on the opposing side for the balls to be inserted. These are then spaced with the holding ring which centres the inner sleeve.

[underused]

Thanks Damien, for sharing that with us
Does those particular bearings belong in a Router? My Makita router has been upside down for a few years...must be in need of a clean out...

[damienhazo]

Thanks Damien, for sharing that with us
Does those particular bearings belong in a Router? My Makita router has been upside down for a few years...must be in need of a clean out...

Yep. They are the bottom-end bearings from the 3600s and 3612s. If it isn't getting warm quickly or showing any other signs, I woulnd't repack it yet.

Getting cold in Japan? It's already started snowing here. The garden is almost white...