I am having alot of movement in my v-wheels, especially the ones for the ones holding the z-axis plate to the x-axis.
This is causing alot of chatter no matter what speeds/feeds/depth I try to use. (In wood! )
I have checked the spacers in the v-wheels using a micrometer and a digital caliper I am pretty sure its not the the spacer that is out of tolerance like I have seen many have had trouble with.
Its not the outer part of the bearing that is moving in the v-wheel assembly.
I can move the inner rings in the bearings about 0.1mm back and forth in an assembled v-wheel.
This appear to be in all the v-wheels but as far as I can understand its only the z-axis (in x-axis direction) which in actually experiencing much axial loads.
This is a SUPER exaggerated image showing what I mean about the movement!
The whole inner part of both bearings move independently of the outer bearing-rings and the delrin-wheel.
It is just 0.05-0.1mm but this creates 1.5-2mm movement on the tool… And since the axial play is very easy to produce this is also creating ALOT of chatter, at least audible. The sound is awful… :-/
And by the way, on my SO2 design I think this is alot less obvious since the z-axis assembly uses v-wheels on both sides of the x-axis and therefor translates the forces on the tool into radial load on the v-wheels and bearings instead of the axial load the wheels experience on the SO3…?
Or am I thinking incorrectly…?
I would greatly appreciate if someone could check one of their v-wheels and see if this movement is suppose to be there or if I maybe have bearings with some kind of fault?
Usually this sort of axial play is caused by an out-of-spec V-wheel — the races are too thin for the 1mm precision spacer.
If memory serves, Tim Foreman worked up a spreadsheet which allowed him to measure all his wheels, then use an assortment of precision spacers of varying thicknesses to fill them in precisely, and to arrange the resulting assemblies optimally:
There should be very minimal to no play in the bearing. The balls ride in a channel similar to the image below.
Are all 4 bearings like this?
Either you have bad bearings or they prematurely wore due to improper (over) tension.
When I adjust my V-wheels I only apply enough rotation to the eccentric nut to engage the wheel so that the wheel must roll if the carriage is moved.
I do this by hold the wheel to try to stop it while moving the carriage, if I cant stop the wheel with my fingers then it is “properly engaged”
If I can stop the wheel from turning while moving the carriage I rotate the eccentric nut further.