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

Just to be pedantic: ;-)

My cue was that the originals were steel alloy . H-D had a reason
for that ...

There was a reason. Maybe without reason.


BTW , crank bearings are usually at least 2" diameter , and run
with an oil film .

My example was only to show, that the bearing material itself doesn't
have to be thick-walled.

These are .674 and .699 diameter , and are greased . They also
only rotate about 10 degrees max , so the load is very concentrated
.

The same is valid for bronce and steel bushings. :-)
Generaly, steel (gliding) on steel without _pressurized_ oiling is
deemed to fail. One exception coming to my mind is a CI-bushing.

Nick

There are tribology tables available that will show you which journal
materials work with which bearings, at which loads and which speeds;
wear ratios; performance with and without lubrication, etc.

From my diminishing memory, what I learned when I was reporting on
this subject is this: Mild steel on mild steel is one of the worst
bearings imaginable, at all but the lowest loads and speeds. OTOH,
hardened steel on hardened steel is one of the best. Before rolling
bearings were available for reasonable prices, hardened steel on
hardened steel was used for the most demanding instrument and
machinery applications, including ultra-precision grinders, at the
highest speeds (then around 10,000 rpm for an internal grinder, for
example).
And that , sir , is *just* what I needed to know . Ya gotta remember , we're
talking 30's technology here . Which means that the ones I pressed in today
gotta come back out for heat-treat .
What a great excuse to build a small gas fired forge ! Been doing some
research , and there are some very simple and relatively cheap designs out
there . Already got the wife convinced ...
--
Snag aka OSG #1
'76 FLH "Bag Lady"
BS132 SENS NEWT
"A hand shift is a manly shift ."
shamelessly stolen
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