On Sat, 1 Aug 2009 11:52:34 +0000 (UTC), des bromilow
wrote:

In building replacement parts for motorcycles we've been using 4140 which
eats cutters, taps etc too aggressively.

Does anyone know the alloy used to make make high tensile bolts?
better yet, does any one know what alloy would be used to make axles for
motorcycles, or fork spindles which will machine easier than 4140, but still
strong enough for the task?

Thanks,
Des


so thats what you get up to when the plonker local council bans your
furnace :-)

never seen a spec for motorcycle parts.
aircraft ht bolts are from SAE4037 or SAE8740 high tensile steel.

personally I'd keep using 4140.
we do lotsa aircraft stuff in that alloy.
my aircraft tailspring is in 4140 tempered to 120,000psi Ultimate
tensile strength and it has never given trouble despite the hammering
it gets. cessna leaf springs were tempered 4140 I'm told.

from my motorcycling I'd be surprised if the axle was anything
special. they seemed to be fairly malleable.
if you want easy machining try SAE1214. it is free machining and
available from bohler/assab steel stores (pink on the end).

(btw last time you saw me I was investigating aspects of your control
system alarm handling :-) )

Stealth Pilot