Dumb question time. Where can I get black jacks that match the red on my 3456A? ![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
I can't help with that, but it prompted me to think about something I've had in mind for a while, which is to custom make myself some 4mm jacks. I've just about convinced myself to get one of those mini-lathes. Yes, they are crap, but they are also 100% better than no lathe at all and I keep on finding problems that could be solved in 10 minutes with a small lathe and a chunk of brass or machinable plastic, such jobs being well within the capabilities of those mini-lathes.
Which gets me to a question for the assembled multitude. Does anyone have any experience with using acetal (aka Delrin aka PoM/Polyoxymethylene) for jacks, insulators, standoffs and the like? The reason for picking on acetal is that it's
really easy to machine, has good mechanical properties, and seems OK electrically (resistivity 14 x 10^15 ohm cm, better than polythene or PVC, on a par with nylon and polycarbonate, worse than kapton, FEP, and PTFE). It's not a material I've seen used commercially, but that may simply be because it's expensive compared to reasonably electrically comparable materials and it's good machining properties are not called for in normal manufacture - people usually cast these kind of parts, not turn or mill them.