"Nick Müller" wrote in message
...
Ed Huntress wrote:

Hardened steel journals running in mild steel bushings actually aren't
bad
if the loads are light and the lubrication is good. The best hardened
steel on hardened steel bearings used no lubrication -- or, more
accurately, they ran with dynamic air bearings, with about a 0.001"
clearance or less, down to 0.0002", and had to run at high speeds
because
they dragged with air film around with them ("dynamic" and "static"
lubrication mean the opposite of what we usually think).

OK. Hard steel on hard steel works. But, as you said, with little load
and high rpm. Not what you find in the fork described. I still would not
do it _now_, even if H.D. did it _then_.
It was in the 40's when bearing bronces made a big evolutionary step.
So, it was _past_ H.D.'s decision for steel on steel.

I have no idea what the "fork described" is, nor who made a steel-on-steel
decision. I just saw that thread drawn out much longer than it should have
taken, with no apparent resolution, so I dumped a load of bushing-material
data the way you might dump powdered lime on a magnesium fire. g

Yes about the '40s. Implementation mostly in the '50s.

--
Ed Huntress