Cheapo Leadscrew with minimum accuracy requirement!

[Swarfing]

What about some chromed rail (25 - 30mm from wicks and acetal rod bearings pulled back and forth with wire would be a much cheaper option and an easy build? like in a printer the wire can be wound a few times at one end and a tensioner at the other. The bearings can be whipped up on a lathe.

[Vikash]

Thanks for the replies.

It does need to be motorized, so I'm not looking for anything to push/pull (only). I already use a push system (commercial design that cost £200 for 50cm) and I'm certain something better can be built for less.

I briefly looked at the superjack thing, but I don't think it satisfies the variable speed requirement and couldn't see it extending from 0 to ~1m either.

I thought the gear and track method wouldn't offer the finesse as slower speeds as a leadscrew/nut?

Mark, not sure where your posts have gone, but the head I use is the 701HDV.

These aren't strictly neccessary, but it would be nice if the system could be used manually as well as motorised (can a nut be pushed to turn a leadscrew easily?), and also it would be useful to be light enough to transport around!