Sieg X1. Now with extra brurp brurp burrzzzzzup!

[ecat]

Heh, forgotten all about this thread until a moment ago when it popped up in google...

Nice work! :)

Thanks, but in truth it is a shoddy mess that no one would be proud of. Still, it got the job done and proves that even an inexperienced numpty like myself can make a fairly successful stab at building bearing and motor mounts.

Are you using the stock leadscrews and nuts?

Sure am. Nothing on the machine was drilled, cut or harmed in any way. I highly recommend the fitting of bearings, even just thrust bearings to even the manual machine. They make for a much smoother experience and kill most of the backlash dead.

How are you preloading the bearings?

Thanks

Preloading: With the axis, bearings and block in place, wipe the machined part of the screw clean of oil and fit the axis part of the 3 piece coupling, setting it just a little snug. Wind a M6 nut on to the existing thread that's poking through the centre of the coupling piece. Tighten the nut until it feels just right, ie not too tight. Tighten down the coupling screw and remove the nut. Test for any play. Job done.

N.B. The above is probably the 100% wrong way to do this but it worked and is still working.

While I'm here:

I fixed the sticky Z movement by taking some fine wet and dry wrapped around a flat surface to the worst of the machining marks on both the ways and the head - the back of the head was a mess and totally devoid of lubrication, here I started with a file - gently! - I also made a ham fisted attempt at adding a couple of oil ways :lol: to the rear. I added a little carriage to the bottom of the head but it was definitely the smoothing that had the largest impact. I'll repeat, the back of the head was a disgusting mess, before smoothing I needed one hand on the hand wheel and one on the column to wind the head up, after smoothing, even with everything tightened down, I could raise the head with little more than finger force.

The machine still suffers from head droop and for this I know of no cure short of replacing both the head and z column. After all this time I'm not sure if it's worth the effort.

[Jonathan]

even just thrust bearings to even the manual machine. They make for a much smoother experience and kill most of the backlash dead.

Not that it really matters, but strictly speaking that's not quite true. Putting thrust bearings on the leadscrews reduces (ideally eliminates) screw end-float which is when the screw can move parallel to it's axis causing inaccurate positioning, even if there was zero backlash.

[russell]

Not that it really matters, but strictly speaking that's not quite true. Putting thrust bearings on the leadscrews reduces (ideally eliminates) screw end-float which is when the screw can move parallel to it's axis causing inaccurate positioning, even if there was zero backlash.

If you want to be pedantic end float on the leadscrew is backlash according to the Oxford Dictionary:

• 2 [mass noun] recoil arising between parts of a mechanism.
  
• degree of play between parts of a mechanism: typical gearbox backlash in these systems is 2°

Russell.