Bad bearings or bend rods?

Hi all,

I've started building my fisher but have noticed one of the carriage's on the three main towers is sticky. The bearings seem okay when I slide them on a single smooth rod but when they are on both their sticky. Could this be a bearing problem or maybe bend rods?

I'll try to get a video of it.

Any help would be greatly appreciated

Video showing the problem

[www.youtube.com]

have you a pair of calipers to measure the distance between rods and bearings?

if no the try swapping moving the carriages between the good rail to the bad rail if the problem stays on the same rail then you have a rail problem, if it moves with the carriage then you have a carriage problem

from your vid I would guess there is a problem with the carriage, you may find the printed body is slightly out of size

Either way strip down the axis and try rebuilding it, but build everything loose, and when its together you need to 'float' the carriage into place, this is done by progressively tightening the bolts in sequence, and checking the carriage still moves freely as you go, before you tighten a bolt move the carriage as close as possible to that bolt.

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