Rock tumbler bearings

You can get inexpensive ball bearing pillow blocks with pressed steel housings that are only 3-5/8" long. See McMaster p/n 5913K41 as an example or download the .pdf on this page for more variations.

Ned Simmons

Hmm. What if you mounted one pair of pillow blocks right side up and the other ones upside down? Get 'em real close that way, but you'd have to modify your design thinking a little.

Actually, you don't have to use pillow blocks. You can used flanged bearings like this one:

but on the sides of your tumbler, not on the floor. Again, a little different thinking.

Grant

I think you're limiting your search for bearings too much. MSC has 1/2" pillow block bearings ranging from 1.126" to 5" overall length. The smaller ones have a stamped steal pillow instead of a cast one. They also have a bearing block with a 2-bolt flange that could be bolted to a riser plate on each side instead of using the pillow blocks.

Or if you happen to have quick and inexpensive access to the type you were originally talking about you could weld a vertical bar with 2 holes in it to your base plate and mount the pillows on it with the bolts going all the way through both pillows. I'm not sure how much closer that would put them but it should help quite a bit.

Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com

"I'm not grown up enough to be so old!"

I think I would make my own double pillow blocks out of wood with bronze sleeve bearings. W.W. Grainger sells bronze bushings for about $3 for three bushings. If you have access to a drill press you could drill both blocks at the same time so both blocks have exactly the same spacing and height. The bushings may not last forever, but would last pretty long. Bronze is what the hobby tumblers use. And replacing them several times would be cheaper than buying sealed ball bearings.

Dan

Do a little research into wood bearings. They just happen to be the very best type of bearing for abrasive applications. There's several options. The real beauty of it is that you can even make them yourselves!

That's what I use on my sh*t shaker (compost screening plant) I used blocks of oak(?) from pallets faced and bored on a lathe faceplate. The 1/4" throw eccentrics run in pairs of these and are greased through grease nipples mounted to hollow 3/8 cap screws threaded into the wooden bearing - this was to increase the tapped hole strength in the wood - the nipples blew out without the hollow cap screw adapters. At ~600 RPM these bearings work great but need a bit of clearance. Gerry :-)} London, Canada

How about taking a block of UHMW and drilling two holes in it at whatever spacing you desire. With a moderate load UHMW will last a long time and when it wears you can just drill two more holes. If you have a heavy load you can use nylon for better wear resistance.

Wood bearings were common in windmills. Just make them a little longer. Check older machinists books for info on wood bearings, types of wood, lubrication.

Chris, Consider using two parallel shafts (length to suit length of drum (s) you are planning to use, but mount two rubber "tires" on each shaft, one on each side of the barrel at the bottom and one on each side of the barrel at the top. If they are spaced right, and if the tires are of sufficient diameter, many different size drums can be placed on the tires and still be rotated. The rubber tires will dampen the noise a bit, provide good "traction" for the drum, will last forever, and will eliminate the need for moving the shafts apart or closer for different size drums. Just a thought.... HTH Ken.

On Tue, 28 Jun 2005 02:14:51 -0500, the opaque "bw" spake:

Lignum Vitae wood has been used on boat propeller and rudder shafts for centuries now.

Ships used wood bearings. Special wood and kept oiled IIRC.

Martin

That is it! - thanks Larry

Sorry for the slow reply to this thread. I immediately thought of Lignum Vitae when someone mentioned wood bearings. An old schoolteacher told me if was used to line sterntubes years ago and it stuck in my mind. Is it readily available and affordable? I'd be interested to experiment with it.

By the way, the reason I didn't suggest using those "egg shaped" bearings (the kind with two bolt holes parallel to the shaft) is that no one will supply the to me at a sensible price in England. We can't get prices anywhere near to McMaster's for a lot of stuff!

I might be able to get regular pillow blocks cheaply enough, but I don't really want to mount then vertically or with one upside down. I think it'll spoil the looks of my tumbler. Maybe I should wait till I get a milling machine, but that could well be a few years!

Must go - supposed to be going on holiday in 4 hours!

Thanks for the suggestions,

Chris

Try the NSK "Silver series " bearings. They make pillow block bearings and 2 hole flange bearings that are more compact then the usual industrial size blocks.