So 3 years ago I posted about movement of my X carriage sticking intermittently during movement and pulling my hair out trying to figure out why.
Initially it seemed like my v-wheels were misaligned so I got replacements and even an entirely new x carriage to rule out defective parts, but this did not solve my problem.
My next trick was going to be to try replacing the two bolts that hold opposing v-wheels with a single threaded rod so that they were in perfect alignment. I got to the point of buying the materials and engineering a solution before falling into depression over the whole thing and mothballed my X-Carve until recently.
I replaced the bolts with threaded rod as I had intended and… still the same issue, my heart sank, but with renewed energy I decided to look into the issue once more and failing that sell the X-Carve to some other sucker.
With the X rail detached from the machine and the carriage fitted I tilted the rail side to side and observed the movement, it was pretty predictable, sticking at regular intervals say roughly equal to the diameter of the v-wheels.hmm… so I pulled the v-wheels off and studied them.
First thing, seemed like over time most of the grease inside had leaked out of the bearings and there was some noticeable grinding in the movement, overall I don’t think the bearings supplied are very good at all. I ordered some equivalent SKF bearings and replaced them.
It did not fix the sticking, but it did smooth out the movement enough to make it less noticeable and tolerable enough to actually operated the X-Carve.
My final observation after having replaced pretty much every part involved, if I rotate one of the v-wheels after tensioning it enough to touch the rail but still loose enough to rotate freely I can watch as the center of the groove deviates in and out between touching and not touching the rail (by a mare fraction of a mm).
Originally I thought it only affected my X rail, but now I notice it does effect all axis just not as much.
It seems to me there is some runout in the v-wheels, how other users haven’t noticed this I don’t know. Unfortunately I don’t own a dial indicator to confirm my suspicion. Maybe over time the v-wheels wear in and the effect becomes less noticeable.
For now I am happy enough I can run my X-Carve again, it’s burned heavily on my mind this last 3 or so years.