Tap Magic?

[Andy A.]

I use it frequently. It does work as advertised for tapping. In particular I find it's the most successful fluid I've found for tapping various plastics. Acrylic is very difficult to tap successfully, but Tap Magic does make it much easier and does not appear to interact with the material otherwise (I do make an effort to dry the part quickly, though). You can very easily tell the difference between plastic threads cut with and without tap magic. You get the same results in polycarb.

I've never used it as a general cutting fluid, but I suppose it would work there as well. It's a little expensive for that kind of work, but if it's all you got...

I also have a can of Alumtap, which seems to be essentially the same thing, or at least so close to it I couldn't tell the difference.