Hi everyone,

I need to machine two small parts. One part requires a yield strength
of 100,000 PSI and one part requires a yield strength of 200,000 PSI.
It's probably best to machine the parts from stock that has a
thickness near the part thickness. There are some small internal radii
and a small cutter of 1/4" OD will probably be needed for much of the
machining and a 3/6" OD cutter for a few other small inside radii. I
need a lightweight material preferably similar in weight to Aluminum.
I'm guessing that Titanium is the best compromise (perhaps the only
one) even though it's a little heavier than aluminum it's still
lighter than steel.

I've listed the overall dimensions of the two parts below along with
the required yield strengths.

Part #1 overall dimensions (required yield is 100,000 PSI)

2.557” Long
3.873” wide
2.139” thick

Part # 2, overall dimensions (required yield is 200,000 PSI)

Part 2.339” thick
2.557” Long
3.873” Wide

Here is what I found in Machineries Handbook...

5 Al, 2.5 Sn Alpha yield = 117 KSI condition is annealed

5 Al, 2.5 Sn (low O2) Yield = 108 KSI condition is annealed

3 Al, 8 V, 6 Cr, 4 Mo, 4 Zr Condition is Solution + age KSI yield =
200 This is a beta alloy

I have no real experience with Titanium, they list Alpha, Alpha-Beta,
Near-Alpha, & beta alloys but I'm not sure what the real differences
are.

For a few parts this small, what is the general difference in cost
(materials plus labor) as compared to making the part from aluminum or
steel ? Aluminum and non-hardened steel are probably out of the
question at both the required yields, but I'm just curious how
titanium would compare.

How hard is Titanium to machine ? How does it compare to Aluminum and
say 4140 pre-hard ? I'm guessing it must fall somewhere between these
two ranges.

I would appreciate any recommendations for a specific grade of
material and any tips for machining.

Thanks
John