Connecting rods ? been a while since I looked at an engine -
I have one to make myself.
It might be they have to push through bushings and can't
get pitted or rusty.

I didn't see a spec on a lot of mine - the body was cast Iron
but one only knows what the various rods and axles are.

Martin


Ed Huntress wrote:
"Errol Groff" wrote in message
...
Two of my students are building model hit and miss engines. The
drawing calls for stainless steel for the connecting rods but does not
specify what grade. The part will be made from .4375 diameter rod
stock.

Suggestions please on what grade to use keeping in mind that they have
no experience with S.S. so machinability is important. Will probably
order the stock from Mc Master Carr and they list a bewildering
variety of grades.

Thanks,

Errol Groff

It seems strange that stainless is called for at all. Is there some reason
for it, or is it some designer's random idea?

Stainless is slightly less stiff than other steels; it's not particularly
strong in the likely grades you'd use; it's subject to stress-corrosion
cracking; the austenitic (300 series) grades make truly lousy bearing
surfaces; it costs more...what in the heck is the reason for it?

--
Ed Huntress