On Tue, 2 Apr 2013 09:54:20 -0700, "anorton"
wrote:


wrote in message
...
There is some food for thought! I just found some small oil impregnated
bronze sleeve bearings which cost only 34 cents and could hold up to 250
lbs. This would allow me to stick with a 1/4" brass shaft, so I think I'll
go with that.
Thanks everyone!


A bronze bushing on brass shaft is somehting that I have never seen and it
is certainly not how the bronze bushing was meant to be used. It is quite
possible there would be too much chemical affinity and they would start to
stick and gall.

Absolutely. Do not use such similar materials for shaft and bushing
unless they are extremely hard and have low cohesion coefficients. No
way do you want to use two copper alloys together.

Music wire or other hard, high-carbon steel is the logical choice for
the shaft. If rust is an issue, then 440-grade stainless steel.

The ideal wheel would be a high-strength (over 100,000 psi compression
strength) bronze, but it probably isn't necessary. Even yellow brass
(~ 40,000 psi compression) probably is adequate. And impregnated
material will help with stick-slip.

A milder steel shaft probably would be Ok, too. If you go too soft on
the shaft, you'll eventually run into a stick-slip problem. But I
don't think it's likely to show up here, even with a mild-steel shaft.

--
Ed Huntress