[rutman]

I have an acme screw but find the bronze nuts expensive at 25$ each.
can anyone give some tips on bronze casting?
can i use the acme screw as the mold and pour bronze around it ,
or will the bronze contract and seize on the screw?

[Eurisko]

That sounds like a lot of work, and you won't be pleased with the results.

Why not just buy a flanged brass bushing, drill it out to the correct diameter, then tap it with a combination roughing / finishing acme tap?

[rutman]

Thanks that's just what I needed - now I just gotta find an acme tap....maybe its easier than i thought as the acme profile is trapezoidal and not curved, iirc

[mc_n_g]

Spend the $25 on the already tapped nut. It is going to cost you 3-5 times that to buy an acme tap.

[rutman]

I'll need 12 or so of the nuts so maybe buying a tap and diy is what I'll need to do.

[p38nut]

I'll need 12 or so of the nuts so maybe buying a tap and diy is what I'll need to do.

Did you get you're nuts done?