Trouble with v-wheels (Axial play, chatter etc...)

(Morten Lund) #1


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! :open_mouth: )

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.

The thing I am wondering about is, what is actually stopping the assembly from moving in the axial direction (thrust)?

The “Inner bearing ring” is easily moved with just my fingers while holding the assembly in my hand.

The SO3 is just used for <10 hours and I have experienced this issues since first usage… :-/

Hope to hear from you guys! :slight_smile:

(Richard Cournoyer) #2

HI Morten,

The design of the V-Wheel is such that the first space, pushes against the first bear’s inner race, which in turn pushes on the second spacer, then onward to the outer bearing’s inner race, and finally to the head of the bold. This is a solid and robust metal to metal design and can only produce play if (a) the bearing is worn, (b) the bolt is loose, © the assemble is missing a part (Spacer), or (d) the delrin inner flange is thicker than the spacer

Great picture!

Please take one of the bolts that is producing some play and disassemble it (Be careful of the Delrin wheel, they are fragile)

Please let me know what you find.

(Morten Lund) #3

Thank you for your reply! :smiley:

But, what I mean is, does the bearing themself stop the movement in the axial direction by design?

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?

Thank you, very much!

(Richard Cournoyer) #4

There should be NO movement here.

Again, disassemble the V-Wheel (several) and look for the odd behavior. (Home many bearings are loose, missing parts, etc.

(William Adams) #5

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:

Links from:

(Dustin S Tilton) #6

I had quite a bit of play. I ended up buying 4 new v-wheel kits from Openbuilds. No more play.

(Apollo Crowe) #7


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.

(Argenis ) #8


@morten Did you solve the “Trouble with v-wheels movement”?
I have the same problem in my new SO3 in the Z axis.

Thanks a lot…

(William Adams) #9

Please adjust the V-wheels — it should be noted somewhere in the instructions: