How to replace bronze bearings / bushings?

[Redboy]

I'll start another thread with some photos, but the really cool old Bett-Marr band saw I picked up yesterday appears to need new bearings.

The lower wheel shaft runs in two bronze sleeve bushings that are pressed into the cast iron frame. I think an old drive belt with lumps and bumps and nasty jumps wore the sleeves out of round, and now there's a fair bit of vertical play in the lower bearing that I don't like.

Seems to me that someone with a bit of know-how should be able to press the bushings out and pop some new ones in fairly easy, but at this point, I am not that someone...

What does it take to do this kind of repair? Should I attempt it myself? What kind of shop would I be looking for if I wanted to have it done "professionally"?

I'll post a few pics later tonight.

 

[Roberts210]

Naw, do it yourself. Do you have a drill press? If so you can use a socket slightly smaller than the I.D. of the hole to press the bushings out. Then measure them and order a new set and press 'em back in. If you can't get this to work on your drill press you can tap tap tap them out using the same socket and a leather mallet.

 

[DBendr]

Run it by a NAPA or small engine-lawnmower shop. They usually have stuff laying around to handle that.They may even have some bushings that will work. They'll surely know where to get some.Those are all standard sizes. No need to OEM.

 

[Redboy]

Naw, do it yourself. Do you have a drill press? If so you can use a socket slightly smaller than the I.D. of the hole to press the bushings out. Then measure them and order a new set and press 'em back in. If you can't get this to work on your drill press you can tap tap tap them out using the same socket and a leather mallet.

I do have a drill press, just hadn't thought to use it as a... press. :-/

I think at least one of the bushings needs to be pulled, or cut out. I'll take another look tonight when I get home.

Run it by a NAPA or small engine-lawnmower shop. They usually have stuff laying around to handle that.They may even have some bushings that will work. They'll surely know where to get some.Those are all standard sizes. No need to OEM.

Oooh, I like this idea. Sounds easy.

 

[DBendr]

OOOPS. Twin Cities. Sorry.
Snowmobile shop.

 

[Redboy]

OOOPS. Twin Cities. Sorry.
Snowmobile shop.

LOL! We do have lawnmower shops too, but I think they're all hibernating right now.

 

[larry_g]

When you have a rotating shaft in plain bearings always suspect the shaft of being worn too. So before just replacing the bearings measure the shaft and make sure it is to size and smooth. Some applications are not suited to just pressing a bearing and back to running. When a plain bearing is pressed in the I.D. reduces some and may need to be reamed back to size.

Sizing the bearing is not so important on a rocker shaft, like a clutch pedal, but is very important on a precision bearing like your working with.

lg
no neat sig line

 

[Redboy]

When you have a rotating shaft in plain bearings always suspect the shaft of being worn too. So before just replacing the bearings measure the shaft and make sure it is to size and smooth. Some applications are not suited to just pressing a bearing and back to running. When a plain bearing is pressed in the I.D. reduces some and may need to be reamed back to size.

Sizing the bearing is not so important on a rocker shaft, like a clutch pedal, but is very important on a precision bearing like your working with.

lg
no neat sig line

Thanks Larry - it's this kind of stuff that tells me just how out of my element I am! The shaft does show some signs of wear, but I don't know how far gone it is. More to look into.

 

[Stuart in MN]

Check Ace Hardware, most of them around here keep a selection of bushings in the hardware section.

You can usually use a chisel to grab the edge of the old bushing to drive it out, then tap in a new one. The drill press idea is good but I've always just tapped them in with a hammer and something like a block of wood; the key is to get them started straight.

 

[My Old Tools]

This is why everyone needs to own an arbor press, or two, or three......

 

[Dagny]

Electric motor shop will have it all including reamers if needed.

 

[Roberts210]

I do have a drill press, just hadn't thought to use it as a... press. :-/

Nobody else does either, but that's why they are called drill PRESSES.

 

[DenisG]

You can probably get it out with some short sections of pipe, threaded rod, nuts and washers.

 

[Redboy]

I took another look at it this morning and it all looks pretty straightforward. Famous last words, perhaps...

Here's what we've got:

 

[Redboy]

I thought this one was kind of funny...

Cast iron wasn't exactly an exact science, was it?

 

[Redboy]

I've been looking at this and thinking... Is there a reason I could not (or should not) use a flanged bushing here? There were a couple of thrust washers on each side - wouldn't a flanged bushing do the job of the thrust washer?

 

[larry_g]

I've been looking at this and thinking... Is there a reason I could not (or should not) use a flanged bushing here? There were a couple of thrust washers on each side - wouldn't a flanged bushing do the job of the thrust washer?

Most thrust washers come in specified thicknesses. So you get the washer by id/od/thickness.

On a flanged bearing you may luck out on the thickness, maybe not. I would also want to see a champher on the casting so there is no interference when seating the bearing due to a radius at the junction of the flange and the OD of the bearing.

Do you understand how much axial play is allowed here (I don't)? Are the thrust washers there to take up axial play or just to keep the pulley from contacting the casting?

A bit of research here may help, http://catalog.buntingbearings.com/category/sae841-powdered-metal-sleeve-bearings

Check out the flange thickness on the bearing that fit your needs.

lg
no neat sigline

 

[404]

I thought this one was kind of funny...

Cast iron wasn't exactly an exact science, was it?

LOL I see your point.

To me that is a very nice looking saw.

I would suggest oiling all these bushings and running the saw to determine if there is really a problem in operation BEFORE going Lizzy Borden on it.

 

[Tejaas]

You can probably get it out with some short sections of pipe, threaded rod, nuts and washers.

Yep, that's what i was gonna say.
I keep 2 of them laying around, sometimes they are the perfect solution.

Perhaps you have everything already laying around/on hand.

You may be able to get away with using a socket of dimension nearest the bushing, just back it with a washer.




~Tejaas~