[ QUOTE ]
FNinjaP90 said:
Any steel would do. Actually, any material that conducts electricity and is fairly good at dissipating heat will do. Strength is not a concern.
[/ QUOTE ]
Steel is pretty poor at both electrical conductivity and heat transfer. Stainless steel is even worse in both respects.
I would recommend aluminum if this part does not need to be soldered, and brass if it must be soldered. Either one is cheap and much easier to machine than any steel.
In any case, the part you have presented is child's play from a machining standpoint, and if I didn't already have a sizeable waiting list, I'd do it for you.
Funny how everybody has some little project in mind when they discover you're a machinist!
Chalo Colina