Quote Originally Posted by richie00boy View Post
I'll have to strip the machine more to get at the leadnut - there is grease on it so I can't see what it's made of. I woudn't have thought it was excessively worn as it's only run about 10 hours.

It does vibrate and stall.
Suggest you take it off completely and check screw against flat surface to see how much it's bent. It may be possible to straighten if not bad.

You also need to know why it's bent.? Has it bent because the alignment is off and one end is higher or offset to the other. If so what happens is the leadnut which is fastened to the gantry bends the screw when it approaches the end which is higher or lower than other. The screw fixed ends and leadNut need to be perfectly aligned on the same plane. This is a common cause of bent screws.!!

Quote Originally Posted by richie00boy View Post
Is the current leadscrew threaded rod that I can buy easily and get the machinist at work to do the ends for me? I don't want to spend more than 50 quid really, but the primary use of the machine is PCBs so I need to get low backlash.
Like I say hard to see from picture.!! . . . BUT it won't be thread rod like you buy at local hardware store.
It could be what's called Acme Lead screw which is often used on cheaper machines, if this one of the early Chinese machines then chances are it is.? If so they used plastic lead nuts which wore out very quickly and could have done so even with 10hrs use that's how crap they where.!!!!

The later slightly better Chinese machine are coming with 5mm pitch ballscrews, Looking closer at the pics I'm tipping it's lead screw not ballscrew.

You will buy a ballscrew with nut from china complete with end machining for around £50 delivered.
TR14 lead screw will cost about £15-20, lead nut will be £10-15 then you'll need to machine the ends. You could be up and running for £20-£30 but you'll still have crappy screw with some backlash in the nut unless you buy better anti-backlash nut which will cost much more.!!. . . So you can probably tell were I'm going.? Not worth IMO so just Bite the bullet and buy a ballnut you'll get much smoother machine with better accuracy and probably more speed.