Running 4 1605 screws

[magicniner]

Repeat the up/down cycle several times to see if the error increases with each cycle, if it does you have a mechanical problem.
If you mark the screws at the front top with a marker pen and run up and down several times do the marks all come to the front again at the same time?

[kev20009]

Repeat the up/down cycle several times to see if the error increases with each cycle, if it does you have a mechanical problem.
If you mark the screws at the front top with a marker pen and run up and down several times do the marks all come to the front again at the same time?

hi thanks for reply, done the up down several times but gets worse, it doubles the gap on the left rod, put red mark at front of rod and one was just off and the other by a bit so marks never came back, thanks again kev

[Clive S]

hi thanks for reply, done the up down several times but gets worse, it doubles the gap on the left rod, put red mark at front of rod and one was just off and the other by a bit so marks never came back, thanks again kev

If the pulleys are tight and not slipping are you sure you have the same pitch on the all the screws?

[kev20009]

If the pulleys are tight and not slipping are you sure you have the same pitch on the all the screws?

hi glive just checked and pitch 5 mm on all using calipers, yes checked pulleys, only thing I can think is when I put 2 side by side with the start fron,t thread is high to other match line of thread and the start is quarter way round, I have tried every position but still none match when travel stops, thanks again kev