[SweetJustice]

I had a Haian 3-in-1 fall into my lap much more cheaply than the drill press that I otherwise would've had to buy. I've started doing a little milling on it, and I've quickly come to realize that the backlash (almost 1 mm!) is going to drive me insane.

It seems like the reasonable thing to do is to buy or fabricate some brass anti-backlash nuts. The leadscrews are standard left trapezoidal threadform, 12mm x3.0 and 16mm x 4.0. I haven't found a place to buy them, so on to plan B.

I'm not afraid to do some CNC thread milling on my Taig, but my question is: how? I can't find a threading insert small enough. The trapezoidal threading inserts I've looked at start at a size of 16mm (eg, 16EL3.0TR), and obviously that won't fit inside the 10mm and 14mm bores.

As an aside, I don't quite understand why there's a 16mm internal insert for doing pitch 3.0... because according to Machinery's Handbook, the largest trapezoidal thread with a 3mm pitch is M12.

[WaveDude]

Making Acetal leadscrew nuts the easy way - The Home Shop Machinist & Machinist's Workshop BBS

[WayneHill]

dumpsterCNC - anti-backlash solutions for home and industrial linear motion

They have 12mm X 3 in 1 start and two start leads.

They are right hand thread. You can contact them and ask for specials...

[SweetJustice]

Well that's substantially easier than what I had in mind. Thanks very much!