Where did you buy your threaded rod?(cheapo leadscrew!) - was it straight?

[Smiler]

I'm having a mare getting some 'straight' M8 threaded rod (to use as a leadscrew - we're not all loaded!)


So...if you're using M8 Rod....where did you get lengths from & more importantly....was it as straight as a die (I need one about 44cm long...I think it's this relatively the length that is proving to be the problem)

I bought some M8 from eBay from these bods

Nice and straight but that wasn't really a concern for me.

Don't know what you are using for a leadnut but don't be tempted to use SS, polish the thread all you want, eventually it will bind and scrap the rod and the nut.

Jeff.

[korky]

I used M6 threaded rod, and made my own 'anti backlash' delrin nuts.
(On a home-made CNC made from slabs of an old kitchen worktop)
Very cheap, and they seem to work a treat.

B&Q had some stainless steel stuff - less than a couple of quid per piece. It looked straight in the shop, and I managed to keep it straight on the journey home.

Wickes had some zinc-coated stuff. Straight, but a nightmare to use. I had to run it through a die to cut the thread back to M6 and I never managed to get it to run smoothly. I went back to B&Q to get some more stainless steel in the end.

Neither were 'straight as a die' after fitting - mostly due to my bad coordination and not cutting it to size before fitting it - but were straight enough for me.
Mine span about 600mm, held at either end with skateboard bearings from MUTR. Doing rapids at high speed (600 RPM) makes it wobble and rattle a bit.

Oh, and don't make assumptions about the number of threads per millimetre. Nothing I was routing on the machine was quite the right size... I'd assumed my M6 threads were exactly 1mm per turn, but they were more like 1.06... so calibrate your axis once it's built.

Keith.