Bearings in Sheet Metal

[Brandon Holley]

On our intake, we needed to press in FR6 bearings in 2 places. The sides of the intake were made from 0.060" 6061 so we weren't totally sure how the press would hold up. We decided to play it safe and added 2 bearing plates that simply acted as a carrier for the bearing and would then bolt onto the intake.

The little plates actually ended up being a bit of a celebrity on the team and we ended up making them into little NUTRONs logos just for some extra flare (bottom right):



They worked out great. It was actually a cool feature too, because it allowed us to disassemble part of the intake from the opposite side where if a bearing were permanently pressed in place, we'd be unable to.

-Brando

[akoscielski3]

Originally Posted by Brandon Holley

They worked out great. It was actually a cool feature too, because it allowed us to disassemble part of the intake from the opposite side where if a bearing were permanently pressed in place, we'd be unable to.

-Brando

So your bearings were never pressed into the actual intake, they were only pressed onto these plates? I like that idea alot actually. Were they pressed in? Or bolted on to these plates? If they were pressed how much smaller, if any, were the holes made for the bearings?

Thanks, great idea btw.

[Brandon Holley]

Originally Posted by akoscielski3

So your bearings were never pressed into the actual intake, they were only pressed onto these plates? I like that idea alot actually. Were they pressed in? Or bolted on to these plates? If they were pressed how much smaller, if any, were the holes made for the bearings?

Thanks, great idea btw.

Yeah the bearings were only pressed into the bearing plates. The bearing plates were then bolted to the intake.

For any part that we are making in-house we can reliably undersize the press fit to 0.0005" under and press with no issue. The most reliable way to get good press fits is to invest in the 2 reamers you would need to do 3/8" bore and 1/2" bore bearings (0.8745" and 1.1245"). This becomes a very repeatable process for your team, where you size bearing holes slightly under and ream to the final diameter. You will have much more consistent press fits this way. This will also help you where you may be using a process besides a CNC mill where the tolerances on the diameter may be a little bigger (ie: waterjet). Again, you'd undersize for the waterjet, and just finish with the reamer.

-Brando

[MrForbes]

Another thing you can do if you want to have some fun, is press the bearings into polycarbonate sheet. We discovered that a Forstner drill bit will make a hole just the right size for this press fit.

This works well for smaller mechanism type gearboxes, and I think it has been used by AM to make drivetrain gearboxes too.

[AdamHeard]

Originally Posted by sanddrag

With holes that much smaller there's no chance the bearings will fit. Did you leave out a zero?

With Material that thin it works no problem. If you were pressing into material the same thickness as the bearing it'd be a different case.

[JamesCH95]

Originally Posted by squirrel

Another thing you can do if you want to have some fun, is press the bearings into polycarbonate sheet. We discovered that a Forstner drill bit will make a hole just the right size for this press fit.

This works well for smaller mechanism type gearboxes, and I think it has been used by AM to make drivetrain gearboxes too.

We did this for our 2012 shooter. A total of 10 flanged bearings pressed into polycarbonate sheet. Worked great.

To put some numbers to the OP question:

Using a bearing like this one in 5052 aluminum (28KSI YS):

YS*(bearing OD*sheet thickness)=bearing load at material yield

28KSI*(.875*.0625)=1530lbf to reach yield in 5052 aluminum, assuming the bearing is seated properly and nothing is grossly misaligned. This is at least double the working load rating for most bearings of this size.

[MichaelBick]

Originally Posted by AdamHeard

With Material that thin it works no problem. If you were pressing into material the same thickness as the bearing it'd be a different case.

Is undersizing .003-.005 better for thin sheet, or is reaming out to .001 undersized still better?

[Billfred]

For what it's worth, 2815 has had good luck with flanged bronze bushings for 1/2" shaft inside 1/16"-wall square tubing. In each case, the bushing only went through one side of the square tubing.

We ran them in our 2011 roller claw, and on our ball elevator and shooter axle this year. Any issues we had with any of these were unrelated to the bushings.

[sanddrag]

Originally Posted by Billfred

For what it's worth, 2815 has had good luck with flanged bronze bushings for 1/2" shaft inside 1/16"-wall square tubing. In each case, the bushing only went through one side of the square tubing.

We ran them in our 2011 roller claw, and on our ball elevator and shooter axle this year. Any issues we had with any of these were unrelated to the bushings.

We've done the same.

[JVN]

If you use a flanged bearing, make sure it is well retained in the plate, and pinched axially on the shaft, you'll be fine even in something as thin as 063.

-John