Bearings in Sheet Metal

[Madison]

Most of my experience with sheet metal was in non-power transmission applications.

How do folks typically handle bearings when working in sheet metal? If you're working in .060" or something, do you build up around the bearing with additional sheet? What about thicker materials like .090" or even .120"?

[BJC]

We use .09 for our gearbox sideplates. It works fine without extra material. We also make the holes .003-.005 smaller so the bearing fits tightly which prevents slop in the gears.

Our 2012 collector had bearings in .063 sheet which supported bevel gears. There were no problems with the bearings all year. Just make sure the bearing flange is flush with the metal - it's not like its going to rip out or anything. I wouldn't suggest going this thin for a gearbox though.

Regards, Bryan

[sanddrag]

Originally Posted by BJC

We also make the holes .003-.005 smaller so the bearing fits tightly which prevents slop in the gears.

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

[BJC]

Originally Posted by sanddrag

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

Nope, we just use a deburring tool or ream them out to make them a little bigger after they are waterjetted. I agree that they wouldn't fit unless you make the hole bigger.

[IndySam]

Originally Posted by BJC

Nope, we just use a deburring tool or ream them out to make them a little bigger after they are waterjetted. I agree that they wouldn't fit unless you make the hole bigger.

Exactly or even a little emery paper does the trick. On thicker materials we note which side is tapered by the water jet and a quick hit with a deburing knife usually results in a perfect fit.

[Michael Hill]

Originally Posted by IndySam

Exactly or even a little emery paper does the trick. On thicker materials we note which side is tapered by the water jet and a quick hit with a deburing knife usually results in a perfect fit.

Water jets taper the material? Hmm...I didn't know that. You learn something new every day!

[Andy Baker]

Originally Posted by Michael Hill

Water jets taper the material? Hmm...I didn't know that. You learn something new every day!

Yes, and no.

Waterjetting naturally cut a taper in the material. However, if the waterjet machine has an angle compensating head, then the cut can be straight on one side of the cut.

Andy B.

[JamesCH95]

Originally Posted by Michael Hill

Water jets taper the material? Hmm...I didn't know that. You learn something new every day!

It's called a 'kerf'. A skilled waterjet operator such as the gut I use for work can do a really good job minimizing the kerf's taper, even without a multi-axis head like Andy describes.

[DampRobot]

Originally Posted by JamesCH95

It's called a 'kerf'. A skilled waterjet operator such as the gut I use for work can do a really good job minimizing the kerf's taper, even without a multi-axis head like Andy describes.

Last summer, I was trying to cut some 1 module (metric) gears with a waterjet in about .4" thick material. Unfortunately, the kerf that yo mentioned prevented the gears from meshing properly.

Could you elaborate as to the methods used to help eliminate kerf? We tried cutting extra slow, but it didn't seem to help much. If you can cut propper bearing press fit holes with a waterjet using proper methods, to seems like cutting gears of at relatively large module would be trivial.

[R.C.]

Originally Posted by DampRobot

Last summer, I was trying to cut some 1 module (metric) gears with a waterjet in about .4" thick material. Unfortunately, the kerf that yo mentioned prevented the gears from meshing properly.

Could you elaborate as to the methods used to help eliminate kerf? We tried cutting extra slow, but it didn't seem to help much. If you can cut propper bearing press fit holes with a waterjet using proper methods, to seems like cutting gears of at relatively large module would be trivial.

You could just cut .125 plates and stack the gears. That would help quite a bit. Most places that we've used for work just compensate for the kerf via rotating head.

-RC

[AdamHeard]

You can also waterjet both gears, and run them opposite. We've done this in numerous places.

[JamesCH95]

Originally Posted by DampRobot

Last summer, I was trying to cut some 1 module (metric) gears with a waterjet in about .4" thick material. Unfortunately, the kerf that yo mentioned prevented the gears from meshing properly.

Could you elaborate as to the methods used to help eliminate kerf? We tried cutting extra slow, but it didn't seem to help much. If you can cut propper bearing press fit holes with a waterjet using proper methods, to seems like cutting gears of at relatively large module would be trivial.

No idea how he reduces the kerf so effectively and I've never asked. I assume it's a trade secret of his so that we'll keep sending work to his shop.

He uses a pretty old 3-axis machine with no fancy features.

If I had to guess it's that he adjusts the pressure of the jet in conjunction with travel rate to reduce the kerf, but that's pure speculation.

[akoscielski3]

It's funny that me and Akash just had a discussion about this the other night.

Last year 772 used 1/8" sheet (0.125") for everything and didn't thicken the area's where bearing went. Though it isn't needed we WILL be adding extra material around them this year. I am also probably going to make a "press" mechanism that will make the bearing become perfectly flush with the sheet. This year we went with cutting the bearing holes to the exact size, though with the "press" I would make it about 0.005" smaller. Along with press fitting the bearings I want to Bolt them in, the exact same way IFI bolts the bearings onto their wheels (plastic small washer to space washer, and washer on top of bearing, bolt and nut holding the washer down). The holes for the bolts would also be used to press the bearing into the metal.

You can see what I designed for a bearing press below. You need an Arbor press for it to work.

[rcmolloy]

I have seen two cases where flanged FR8s (pressed in 1/8 plate) and flanged FR6s (pressed in 1/16 tubing) have had pretty great success. The most recent application was done with the FR6s for the 973 Hodgepodge Bot. So far, there hasn't been any records of the bearings or tubing failing.

[Akash Rastogi]

We added extra material in the drivetrain, but straight .09 gave us zero issues for the rest of the bot.