sticky bearing...

[G. Hoffman]

I'm building a fixed gantry machine using SBR20 bearings from China, and I'm having problems with one of my bearings. I've got the four bearings for the X axis mounted to the platform, and it with three of the bearings it is smooth as can be, but the fourth bearing is sticking. It is not an alignment problem on the table, as it sticks when it is not attached to the platform. The other bearings, running across the same section of the rail, have no problems, so I'm assuming the problem is in the sticky bearing, and is probably my fault as it was fine when I got it. There is nothing contaminating it (well, maybe some saw dust - I'm in a working shop with 7 full time woodworkers, after all! - but nothing the other bearings haven't also seen), so I probably turned an adjustment screw or something I shouldn't have, or somehow moved the rubber gasket somehow.

Honestly, ask me to do anything with wood, and I'm your guy, but working with metal or these sorts of bearings really isn't inside my comfort zone.

Any suggestions?



Gabriel

[ger21]

First thing I'd try is spray it liberally with WD40, or a lubricant like LPS1, while moving it back and forth. If it's packed with dust, it should free up noticeably, albeit temporarily.

[G. Hoffman]

I should also mention, it moves much more freely in one direction than the other.

I'll try some WD40 tomorrow when I get back to the shop.



Gabriel

[Walky]

Can you move the internal bearing races by hand easily?
It might be one of the rubber seals sticking (I've had a similar problem but only with closed bearings, and never to the point of it becoming a problem).

I suppose the adjustment screw is not overtightened?

Also, check if the bearing's opening is correctly centered in the block, maybe it's a little offset and rubbing the aluminum support on the side.

[G. Hoffman]

Can you move the internal bearing races by hand easily?
It might be one of rubbers seals sticking (I've had a similar problem but only with closed bearings, but never to the point of it becoming a problem).

I suppose the adjustment screw is not overtightened?

Also, check if the bearing's opening is correctly centered in the block, maybe it's a little offset and rubbing the aluminum support on the side.

The internal bits move easily, and I've loosened the screw without solving the problem. But I'll check how well it's centered.


Gabriel

[hub]

Try to clean it well and then lubricate. If it doesn't work, just get another bearing. Some of them has faults in my experience. Same goes with Chinese ball nuts. Some are fine, but some are not. No matter what you do, some just are no good.

[G. Hoffman]

Try to clean it well and then lubricate. If it doesn't work, just get another bearing. Some of them has faults in my experience. Same goes with Chinese ball nuts. Some are fine, but some are not. No matter what you do, some just are no good.

Well, that leads well into the next question - is there any particular trick to cleaning and lubing these things? I assume it is different, at least in some respect, from my bicycle. Also, is there any particular lubricant I should be using? I'm assuming, again, that it isn't the same stuff I use on my bike.

And thank you all for your help in this - I'm afraid I'm a wood worker, not a machinist, so this stuff is fairly new to me.


Gabriel

[hub]

Well, that leads well into the next question - is there any particular trick to cleaning and lubing these things? I assume it is different, at least in some respect, from my bicycle. Also, is there any particular lubricant I should be using? I'm assuming, again, that it isn't the same stuff I use on my bike.

And thank you all for your help in this - I'm afraid I'm a wood worker, not a machinist, so this stuff is fairly new to me.


Gabriel

I use "CRC Quickleen" spray, easy to use and gets everywhere and does it's job well.
For lubricating, try regular bearing grease for starters and see if it works well. If you are doing extremely high speed (?) you might have to use something else.

Hub