[TheForge] Which Drill Rod?

[Bruce .]

I don't work with hard steel much, so I'm turning to this group for advice
as to which alloy to choose for my applications.

For two separate applications I need small OD (preferably 1/8") shafts that
are quite rigid and will deflect little or not at all under the conditions
of use.  In one case, the working length of the shaft will be 4"-6"
(between supports).

The load on the shaft will be distributed across its length -- like as for
a sheaf of pulleys -- and will total probably only a few pounds-force.  In
the other case it will be closer to 12".  In neither case will the rod
rotate, but in one case pulleys will rotate on it.

Naturally I don't expect NO deflection, but simply want to minimize the
deflection by using a hard steel, rather than whatever might be on the
shelf.  I especially don't want the steel to bend and kink, as does common
steel in such applications.  (The voice of experience is talking, here.)

McMaster has O1, A2, D2, W1, and M2 in lengths of 12" or more.  For the
quantity I need, all of these are affordable, though O1, A2 and W1 are
considerably cheaper than the others, so I'd lean toward those, other
things equal.  These come unhardened, so I expect to have to harden it, and
the ease of doing so is an issue.

Any advice or pointers?

Bruce
NJ