Comments on: Keep On Rolling With Ball Bearings

by: favoriteworkout.com

Mon, 26 May 2008 03:48:53 +0000

These look like nothing more than ball transfers.

http://www.mappcaster.com/ProdInd/Ball-Transfer-Index.aspx

by: Brau

Tue, 05 Feb 2008 10:06:25 +0000

I have these type rollers on the feedout from my saws, but I have one complaint: They have no provision for the dust to fall through and begin to clog and bind after a while. I find a bit of melamine coated particle board works just as well or better for most tasks where marring or excess weight is not an issue.

by: Evan N.

Tue, 05 Feb 2008 05:43:59 +0000

Not only what Stuart says, but with a teflon pad your workpiece will have a larger contact area, leading to more friction. Theoretically your workpiece only touches each bearing at one point, dramatically lowering frictional forces resisting the feeding of your workpiece.

by: Rob

Tue, 05 Feb 2008 04:33:34 +0000

Home Depot / Rigid used to make an outfeed stand that used some sort of HDPE surface instead of rollers I think. The face could be set up at an angle and it would flatten out when your work rode over it so you didn’t have to worry about getting the height just right.

by: Stuart Deutsch

Mon, 04 Feb 2008 22:49:32 +0000

Ball bearings vs. slick materials such as teflon, delrin, or UHMW PE, isn’t a fair comparison since they don’t really share the same properties at all.

Ball bearings convert a sliding motion into a rolling one. Assuming that the bearings are constructed well, the frictional forces associated with rolling will be much MUCH lower than those associated with sliding.

Generally, I prefer ball bearings or rollers for heavier loads with large surface areas, and slick materials for lighter loads with a smaller surface area.

by: SuperJdynamite

Mon, 04 Feb 2008 22:48:20 +0000

Teflon is also pretty expensive.

by: John Laur

Mon, 04 Feb 2008 18:49:05 +0000

PTFE plastics scratch easily and worse, these scratches will catch grit which can scratch up your workpieces. I suppose with some effort you could machine ridges into your plastic infeed/outfeed tables to alleviate some of this problem, but it sure seems like a lot of work when you could just use some kind of rollers from the start.

I recently designed a swing-out cabinet that used these types of ball rollers for support as it had to contain a lot of weight that the low-profile lazy-susan mechansim could not handle on its own. They are inexpensive and useful for a lot of things. You can obtain many varieties too — low profile rollers that can be recessed or rollers with threaded bases that can be replaced easily.

by: Benjamen Johnson

Mon, 04 Feb 2008 18:32:46 +0000

Funny, I remember reading that post too, but I completely forgot about it. I might not have posted this because I don’t like to copy other sites unless I have something significant to add. (Value-added to all you corporate types)

Wait a few days, I might have another solution for you in waiting in the post queue.

I’ve not tried it, but doesn’t Teflon scratch easily? What if you got sawdust or worse, metal shavings on the pad, wouldn’t they scratch the surface?

I think ball bearing roller have the advantage, the debris should fall harmlessly between the rollers. Then again there is the chance if the workpeice it warped at all, it could catch momentarily on the roller balls and screw up your cut too.

by: Zathrus

Mon, 04 Feb 2008 18:17:17 +0000

I saw something vaguely similar on Rockler’s blog, and it got me wondering — why use rollers/ball bearings at all? Why not a teflon coated pad? That should give you the best of both worlds — the stability of a roller (for thin material) and the omni-directional abilities of ball bearings.

Is the friction from a teflon pad that much higher than the roller/ball bearings?

No, I haven’t tried this out myself — but it seems a lot better than either alternative.