How are 2-piece bearings made?

[metrogdor22]

I mean the kind used for rod/main bearings in engines. My first thought is a piece of tube is turned to inner and outer dimensions, then cut in half with a saw. But then it's no longer perfectly circular because you're missing the tiny bit (thickness of the saw blade) from the center, so you wind up with an oval. I suppose you could cut the tube lengthwise, use some kind of collar to hold the halves together, then turn it to size.

How do you guys do it in your shop?

 

[Steve J]

cut it first then solder together then turn it. un solder and you have it.

 

[Steve J]

Just have to add start with a solid block. turn outside to fit. Then cut in half and solder back together. drill and bore starting on the soldered seam. Un solder and done

 

[Jasonb]

Have a read of this where I showed "marine type" bearings being machined

http://modelengineeringwebsite.com/Grasshopper_10.html

Or round ones

http://modelengineeringwebsite.com/Monitor_hit_n_miss_4.html

 

[dnalot]

I know this isn't what your talking about but it's interesting just the same.

Rods for outboard motors are made one piece and then half the large end is snapped off to produce the cap. When assembling such rods, care must be taken to insure the cap is perfectly mated to the rod before tightening the bolts holding the two parts together. Failed alignment equals trashed rod.

Mark

 

[Philipintexas]

In most cases you will be clamping the two halves for the next machining process, super-glue will hold them enough for handling. After reaming or boring to size mark the halves, before separating, so you can re-assemble them in the same relationship as machined. Also, if you make multiples also mark both halves of a pair as well as their orientation.

I've used epoxy and super-glue to hold odd shapes while machining them. Just take light cuts.

 

[valentin]

I work in a plant where half rings are usual. You turn a ring, cut in halves but taking care to displace the saw before cutting in such way that after cutting you end up with a perfect half ring and, in the other hand, with a not so perfect half ring: it suffered the lack of material corresponding to the whole thickness of the saw. This last goes to trash. Repeat the whole process with another stock and you will have two perfect half rings and two defective in the trash. That´s the way they do it in my work. Cheers.

 

[jgedde]

In most cases you will be clamping the two halves for the next machining process, super-glue will hold them enough for handling. After reaming or boring to size mark the halves, before separating, so you can re-assemble them in the same relationship as machined. Also, if you make multiples also mark both halves of a pair as well as their orientation.

I've used epoxy and super-glue to hold odd shapes while machining them. Just take light cuts.

I also use superglue. A little heat and the two halves break apart. A razor blade scrapes off the residue.

To make my two piece bearings, I take some round stock and machine a little less than half way through to make a half round. I then cut the half round in half and superglue them together face to face. The OD will not be at all round, but using the same thickness half round back to back means the parting line will be on center.

I now put the part into a collet, machine the OD, ID and part off. Then a little heat and the halves separate.

Putting the non-round piece into a collet doesn't present a problem. Works fine. The important thing is to make the half rounds thicker than 1/2 the diameter of the rod you're using. When they're glued together face to face, the OD will be more or less an oval. If you cut more than half away, the collet will put pressure along the shear axis of the parting line - not what you want. Cutting less than half of the rod away means the collet ends up pushing the pieces together. Don't go crazy making the halves too thick, else the collet won't hold well and the part will not run true. Just slightly less than half the thickness needs to be machined away to make the half rounds.

John

 

[grizelli]

I have found that making split or shell bearings from solid bronze bar is a very expensive process, as almost all of the metal ends up as swarf. Instead, I buy suitable oversize Oilite sintered bronze bushes, split them lengthwise and solder the halves together before machining. Separating the halves with a torch can get a bit smoky, but the bearings seem to retain a good deal of their original oil impregnation afterwards. Best part, the bushes cost just a few cents/pence

Martin

 

[bazmak]

Machining and using heat goes against all the expert advice and not recommended.However if it works for you all well and good.I personally would be very disbelieving that the bush does not lose its lubrication properties

 

[goldstar31]

This is where one thinks of a 'cat head' chuck.

 

[Hopper]

The machining of Oilite seems to be a contentious issue. The manufacturers say its not the best but that it can be done, using a sharp lathe tool or boring tool. They say not to grind Oilite as this damages the surface somehow.. It seems like once the original oil has come out, via heating with torch etc, they can be "recharged" by sitting them in oil overnight. The local bearing shop where I live does not keep sintered bronze bushings (aka Oilite) in stock but keeps sintered bronze bar which it sells so you can turn up your own bushes to the required size. They assure me "everyone does it".

 

[Cogsy]

When I was in bearings we sold sintered bushes but only solid LG bronze bar. It's also true (at least what we were told by manufacturers) that you could successfully recharge the oil by leaving the bushes submerged for a while.