4 spd. 4th gear bushing - what material?

[Antietam Classic Cycle]

The 4th gear bushing for the 4 spd. transmission used in the V700 and Ambassadors is NLA from every source that I know of. I ordered one from Stein-Dinse, but it's i.d., o.d. and flange thickness dimensions are totally wrong. 

So, I've resigned myself to making my own. However, I'm not exactly sure what material to use. Was thinking "multipurpose 932 bearing bronze, also known as SAE 660" might be the best bet.
http://www.mcmaster.com/#8911K415

Am I on the right track is there a better choice?

[Tom H]

You went to the right place to find the material. Contact them, they probably know the best material for the job.

Tom

[Groover]

^ that's what I would do too. I would think that this being running in gear oil can be a type with higher Zinc content so it can be more durable (to deal with load), but still within the friction parameters suggested for bronze bushings.

1-4% Zinc seems to be the value on the one you selected, but I wonder if you can specify the 4% instead of the 1%. Older Vespas used bronze bushings at the piston wrist pin on the connecting rod and they would wear out quite often, which makes me think they has less Zinc in the them making them softer, but also less friction. Those vespas run at 2-4% 2-Stroke Oil/Fuel mixture, so makes sense you'd want a bushing that wouldn't seize with little oil. In a gear box I think you'd want higher zinc content.

However, I know squat. < my disclaimer.

Good luck.

Here is some more info:

http://www.copper.org/applications/industrial/bronze_bearing.html

[Antietam Classic Cycle]

I disassembled another (later) 4 spd. I had laying around and found something interesting. Guzzi revised the o.d. of the bushing to prevent the sort of fractures I've been seeing in the "early" bushings. The "early" bushing has an o.d. of 23 mm and the "late" bushing has an o.d. of 24 mm. This means the bore of 4th is also larger on the "late" 4 spds. as well. You learn something new every day...

"Early" bushing and gear:


"Late" bushing and gear":


Unfortunately, that doesn't help one bit in sourcing bushings. It could actually make it more difficult since there's two different ones. The one I received from S-D is the "late" type.

[Groover]

The late also has that nice oil channel carved in, which I was going to mention also. Can you machine down the new one you got to 23mm OD?

[Antietam Classic Cycle]

The late also has that nice oil channel carved in, which I was going to mention also. Can you machine down the new one you got to 23mm OD?

Yes, that's the other difference I didn't mention. I've been trying to figure out how to hold the new bushing to reduce the o.d. but haven't come up with any good ideas yet. Another problem is if the oil groove is deep enough (and it looks to be), reducing the o.d. may compromise wall thickness and strength. Probably better off making new "early" types from scratch.

[LaMojo]

Contact Lee Bruns on this site.  I'll bet he can help. 

[Groover]

Those oil channels do look a little deep to take down the OD 1mm.. If you do decide to trim it down, I'd probably go with two aluminum cones with some sort of shaft/axle to hold it in the lathe. Being soft metal like that, it will probably shave off pretty quickly so the cones probably can be tightened enough without distorting the bushing.

Something like this I think:

lathe/chuck-axle-nut-cone>bushing<cone-nut-axle-lathe/tailstack

Sounds complicated and dangerous 

[Chuck in Indiana]

I've been trying to figure out how to hold the new bushing to reduce the o.d.

What you need is an expanding mandrel. Sorry, can't help you with your size.
I used to make die set bushings with Ampco bronze, and it was harder than hammered hell. Made strippers for a paper mill with whatever bronze they furnished. It was hard to machine, too. No experience whatsoever with whatever bearing bronze is. Sorry, I can't help, Charlie.

[Antietam Classic Cycle]

Those oil channels do look a little deep to take down the OD 1mm.. If you do decide to trim it down, I'd probably go with two aluminum cones with some sort of shaft/axle to hold it in the lathe. Being soft metal like that, it will probably shave off pretty quickly so the cones probably can be tightened enough without distorting the bushing.

Something like this I think:

lathe-axle-nut-cone>bushing<cone-nut-axle

Sounds complicated and dangerous 

The cones are a good idea. I could probably use the pair from the wheel balancer I made a few years ago. But, I think I'll leave the S-D bushing as-is for future use and make or have made a bunch of 23 mm o.d. ones. Those are needed a lot more often in my experience.

I plan to stop off at a local machine shop tomorrow that has serious CNC lathes. They can likely turn out a dozen in the same time it takes me to make one. 

[Don G]

Did you check out Oillite bushing material?  DonG

[Curtis Harper]

Maybe the best material would be the original? The updated gear with new bushing is quite available. I have several of them.

[Antietam Classic Cycle]

Maybe the best material would be the original? The updated gear with new bushing is quite available. I have several of them.

Well, I called this morning and was told that y'all didn't have any. Guess I should have called back and spoke with you (he said you were busy loading a motorcycle). Will try again tomorrow.

In the meantime, I found that I already had a chunk of  "multipurpose 932 bearing bronze", so I machined one of the "early" type bushings out of it.







Only took me about 45 mins.

[canuck750]

Nice work!

[Groover]

 

[tris]

These any help http://www.bearingboys.co.uk/?catid=1256&att1=&att2=24mm&att3=&att4=&att5=


Forget that - too late