Looking for 1/2" id flanged bearing .25" thick or less (with flange)

[Eric O]

We order them from small parts usually. Not always the quickest, but they do carry what you are looking for. Their site is www.smallparts.com . Search for part# BRF-08 . Be sure to include the "F" in the part number because that means the bearing is flanged. Hope this helps.

-Eric

[Travis Covington]

The Dynaroll one doesn't specify that it is flanged, although the F would make one assume it is.

Also, the other two links have overall widths of 5/16"

[Kevin Sevcik]

I browsed to the dynaroll one by selecting the flanged R series from their available bearings. here's all their flanged R bearings:
R Series Flanged

[Travis Covington]

I will have to give them a call. Thanks.

[Andy Baker]

The unshielded FR-8 from Consolidated has an overall width of 0.2500.

Also, the Quality BBSRFX-8XXX, unshielded, has a "W" of 0.2500.

Get ready to pay, though. The Consolidated bearing costs about $10. I don't know how much the Quality bearing costs.

I am also looking for cheaper 3/8" id flange bearings, unshielded. I already use Consolidated, but will try Quality and Dynaroll (and others, possibly). Does anyone know how the prices compare with these companies?

Andy B.

[sanddrag]

Travis (and everyone), be aware that p/n BRF-08 from Small Parts is .250 NOT including the flange and the flange is another .063

However, for future reference to others, SPI p/n BRF-08 and BRF-06 are pretty nice bearings for really good prices if they suit your needs.

For Travis, you may want to check out a place called Ace Bearing Supply in Sun Valley, CA. We've had some pretty good luck with them in the past. It is 40 miles away from you which may be a little far but you might want to call and see what they have.

[Kevin Sevcik]

I'll note that I've never actually bought anything from dynaroll. I was looking for bearing specs for a senior design project through www.globalspec.com and ended up getting a catalog in the mail.

[Bacchus]

Just a thought... Since space is so limited perhaps a bronze bushing? They're usually decent enough for most applications on robots. Also, with a bushing, you could just buy something close for $0.50 and then modify it as needed.

[sanddrag]

Originally Posted by Bacchus

Just a thought... Since space is so limited perhaps a bronze bushing? They're usually decent enough for most applications on robots. Also, with a bushing, you could just buy something close for $0.50 and then modify it as needed.

Nice thought, but on Travis's transmissions he doesn't settle for any of these "bronze bushings" that are "decent enough." The Covington line of transmissions retain a high level of quality that is not satisfied by a bronze bushing.

[Bill Gold]

Originally Posted by sanddrag

Nice thought, but on Travis's transmissions he doesn't settle for any of these "bronze bushings" that are "decent enough." The Covington line of transmissions retain a high level of quality that is not satisfied by a bronze bushing.

On second thought, I'm not going to be an $@#$@#$@#... but you shouldn't say things like that when you don't know how someone works, or how they go about designing something.

[Travis Covington]

I shall reveal my design to no one!

But yes, a bronze bushing wouldn't maintain its eccentricity as much as I would like and roller bearings have less frictional losses.

Last year the gears had no bearings or bushings! We simply ran the gear directly on the steel shaft. Scary huh? That is where centerless grinding and different materials come into play.

[Bill Gold]

Originally Posted by Travis Covington

Have you? I didn't think so...

Nope... but I did make you a few 3D models for the hell of it

Originally Posted by Travis Covington

I shall reveal my design to no one!

Um... I saw your design... I gues my username should be "No One"...

[Dick Linn]

Travis,

I'n no engineer, so take this with a grain of salt. I'm curious as to what you are working on this year that is so critical with respect to bearing eccentricity and the actual difference between a reasonably high-precision ball bearing and a decent bronze bearing. [Especially considering last year's effort without bearings ] Bronze bearings aren't all that bad, mostly depending on lubrication, of course. As far as friction goes, sealed ball bearings do need to come up to operating temperature, don't they? Do they achieve this in a match?

I would think losses in other stages of the drivetrain/chassis would be more significant than this (alignment, gear losses...). I can see being worried about the bearing stiffness on a 300 MW generator (like this: http://bpb-co.com/bpb/articles/2Q01bently4.htm), but not on a robot that operates all over the spectrum for 2 minutes or so. At any rate, I'd appreciate any practical info with respect to bearing applications and the like.

[Travis Covington]

I am no engineer either. But I can try to explain, at least how I understand it as a mechanical engineering student, the need for roller bearings.

Ignore the comment about eccentricity and frictional losses as that was not the primary reasoning behind roller bearings.

I will start by telling you the solution we came up with last year was not nearly as elegant as I had hoped it would be. More recently the gears have started to wobble on the shafts (ever so slightly). Obviously, that is not good for wear on the gear teeth nor is it good for frictional resistance. The reasoning behind roller bearings vs. bronze bearings is that there is a very small overall width. If it were to be two bearings, with a shaft running in between them at a distance of an inch or two, I would agree that bronze bearings probably would work well enough for our purposes. But in this application (a technokat style shifting tranny) the 3/8" gear face is the total width that the bearing is supporting. The actual gear itself has to be kept perpendicular to the shaft (that is moving at a different rate than the gear) solely through the presence of a single bearing. So, in this particular case the roller bearing is better suited as it does not rely on the materials frictional coefficient or lubrication to run true and smooth. The roller bearing has tighter tolerances and is more likely to keep the gear perpendicular to the shaft with a lesser amount of contacting shaft area. A gearbox that is 3-4" wide with a shaft in the middle can easily use bronze bushings on the 2 side plates because the combination of the two bearings, at a distance of 3-4" easily keeps the shaft perpendicular to the side plates and gears. This case is quite a bit different.

I hope I made sense of this, but you can get a better idea if you download Andy Baker's whitepaper on team 45's 2003 2-speed shift on the fly transmission.

I know alot of other people have worked with similar things and maybe one of them can comment a little more on the reasoning behind this particular example.