The ideal ACME nut material?

[phantomcow2]

I am considering making an anti backlash nut for my HF micro mill. I would like to use the stock leadscrews until they are worn out, then i will look at ballscrews.
The current nuts on there are some type of iron, which i would expect has a lot of friction.
Using the method as shown here:
http://www.embeddedtronics.com/acmetap.html
I would liek to make my own tap and produce a type of anti backlash nut. But what is the ideal material for this? Is it delrin, or is delrin too weak? I have never used it before

[swarfmacdaddy]

I used Delrin on my Z axis, and it has worked great. And it has traveled miles up and down with no wear that i have noticed.

[phantomcow2]

Did you make the nut yourself?
Even this amchine is small as far as mills go, its a brute for its size. With mostly cast iron, so I was just afraid that the delrin would not be strong enough. It will have to be strong enough to withstand the resistance put in place by the gibs. I dont think its a lot, i dont go ultra tight on the givs, i can move the table by hand.

[anoel]

Brass or Bronze... is probably best of the bunch.

[phantomcow2]

Why brass or bronze?
That would be an easy thing then, since school has tons of brass stock.

[anoel]

Brass and bronze are classic low friction material for nuts... And they are not as subject to temperature like Delrin. They won't marr the screw and will last a good long while.

I've got a Micro Mill as well and have been thinking along the same lines.. I did make a set of 1/2"-10 acme screws and Delrin nuts for the Micro a while back. But they were no more efficent than the stock screws and nuts. So I switched back to the stock screws. Even under CNC conversion the Stock screws provided the same rapids and back lash measurements. (I did switch the Z axis to use 3/8"-16 stainless screws and a brass nut. and thatwas much better than the stock Z setup.) I'll be going back to this setup when I re-CNC the machine in another month or two.