Inventables Community Forum

Should V-wheels have side to side play in the bearing?

several of the V wheels on my machine have what i would call side to side play. basically the outer delrin wheel part moves side to side on the bearings.

on my z axis if i pull back and forth on the spindle you can see the bearings move back and forth inside the delrin wheels. this causes some concern as it doesnt appear to be all wheels that do that but probably half the ones on my machine have this issue. taking a problem vwheel off the machine, i can easily duplicate the problem with my fingers

there was a discussion on this on another thread here https://discuss.inventables.com/t/v-wheels-popoing/11057
hoping to maybe get an official word from inventables if this is something to worry about @Zach_Kaplan

how do you get the vwheels apart?

V wheel have two bearings on each side, you can use same screw from center, move right-left several times it comes off. Remember how did you put those two bearings at the beginning when you're installing. You'll see one washer between, that washer is too thick.

my Vwheels were already assembled when i got them so wasnt sure how to get them apart (without breaking them)

But you know how to remove and put back again. Take the V wheel, you'll see two bearings inserted into black plastic wheel. Those two bearings are removable. One from each side. All you have to do is remove one side bearing by holding from center could be either small screw driver or even that bolt you're using to attach it to X Carriage. When you're twisting side to side it comes off easily. Those are not pressed, just inserted bearings. You have to remove that thick washer and insert thinner washer then put bearing back. That's all. Washer stays between two bearings. If bearings are far away from each other, Plastic wheel slides side to side. It doesn't give problem for X or Y axis very much, but Z axis must be tide enough not to move while changing your bit. Or you will lost your Zero point. I hope clear enough for you.
Check to see if you can make it. I can take one of my wheel later to take pictures step by step, but not today.

Thanks alan, i think i should be able to get it now

Hi @BadWolf There is a little ridge inside the V Wheel that is designed to prevent this from happening.

We would need to inspect your V-Wheels to see if something is out of tolerance. We will inspect the ones we have in inventory today to see if we can find any problem V-Wheels.

Thanks zach, i plan doing what alan suggested, probably this weekend, to see if it helps. I will let you know if it fixes the issue

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I have a few on my machine that have the "popping" problem too. I think I was the cause...I had a pretty violent machine crash (totally my fault) and ended up putting what I would call an extreme amount of excess lateral stress on some of the bearings. (You know what's worse than breaking a bit? Not breaking a bit and having the machine stalled while still trying to move at full speed. smiley ) I hadn't noticed any issues until that happened. Coincidentally, I'm pretty sure that's also what killed my second stock spindle.

I've replaced a couple of the wheels, and have also managed to satisfactorily "repair" a couple more by very, very carefully applying a fillet of super glue around the bearing where it meets the flat face of the wheel. No telling how long that fix will last, but it was cheaper and faster than new wheels. wink I know there are still at least two more that need attention, but they're on the X carriage, and I'm not tearing that apart until I get around to doing the x-rail stiffening mod.

Because my machine is still not assembled I spent about 4 hours measuring the V wheels I received. First thing I did was make up a go no go plug that fits the wheel bore. Then using a depth micrometer I measured from the top of the wheel down to the plug and then from the top of the wheel down to the top of the center rib. By subtracting one for the other I got the width of the center rib that according to the drawing I downloaded from Inventables.
Drawing says rib should be 1.0mm +.0 -.08. so the rib can be .92 to 1 mm.
I measured all 20 V wheel my highest reading was 1.092 mm and lowest was .939 mm with an average of 1.00498mm. 10 of the wheels were greater than 1.0mm and 10 were less than 1mm.
I also measured all the washers that go between the bearings on assembly. They are sold as 1mm thick. All washers were greater than 1mm high was 1.03 and low was 1.01 with average of 1.0177.
I also measured all the ODs of the 40 bearings. They are sold as 16 OD 5 ID and 5 thick.
All bearings were less than 16mm high was 15.99 and low was 15.95 with the average being 15.9695.
My go nogo guage has a small end of 15.93mm for go and 16.0 for no go. All wheels fit the go side and none were loose on the no go side. Specs from the drawing show a bore of 15.95 +0.026 -0.026 this gives a small ID of 15.924mm and none of my wheels were tight at 15.93mm of my gauge plug.
Conclusion is that 10 of my wheels would slide on the bearings and 10 would not.

Here are photos of the operation.

I made a short video of the issue

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That is the typical problem I had. I removed all those thick washers and used thin fiber washers instead. Of course I don't have those high tech mesurement tools, I had to buy several different thickness washers, install/remove couple of times, but I found exact match finaly. The picture I sent yesterday is the solution for that travel. (It's not working without washer, don't try)

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It appears, from the video, that the outer race of the bearing is sliding in and out of the v-wheel.

based on the construction of the v-wheel, you will need to buy new ones. once the ID of the v-wheel is greater than the OD of the bearing, there is nothing you can do...

if you wanna go "redneck," you can apply some JB Weld to the OD of the bearing and re-install into the v-wheel... wait 24 hours before re-installing the wheels on the machine..

You don't happen to be into precision long range shooting are you? Those stats sound like reloading and brass prep stats:-)

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No I'm just a machinist that had wheels, bearings and washers that I could measure against the specs.

Dave

@JayHyde Most of the bearings I removed from my V wheels were an easy slip fit. There were only a couple that were a press fit. The movement we are seeing in the video I believe to be a combination of the rib in the center being undersized the spacer washer being over size and the bore being a slip fit on under size bearings.

Dave

These also exist:
https://www.bwc.com/dualvee.html

the "double-row angular contact" bearings will provide, literally, 10 times more thrust load than the standard ball bearing...

That is true. Have you priced the V wheels from that company. I believe they run about $35 each so you would be talking some $700.00 to replace the 20 on the machine. The other down side is steel on aluminum maker slide will wear the MS out quickly. They are also larger so the holes in all the end plates and carrrage would need to be remachined.
If one was starting from scratch and could incorporate steel rails and the steel V wheels that could be a win win.

Dave

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@Zach_Kaplan i wanted to update you as i said i would. i removed the wheels that were moving and replaced the washers inside with the fiber washers that alan posted. all is good now.

it appears the plastic ridge inside the vwheels may have been compressed and thinner than the metal washer, if that makes any sense. the fiber washers are slightly thinner than the washers they replaced which allowed the bearings to seat against the ridge. im guessing maybe forces from crashing the z axis into the wasteboard compressed the plastic ridge enough to cause the movement of the bearings.

also as david mention, none of these bearing were what i would consider a tight press fit, while they did require some degree of pressing to get them in, it was just finger pressure. if i dropped the wheel on the table with the bearings installed, 5 out of 10 times the bearings would pop loose. not a very scientific test i know. i wonder if the pressure that caused the ridge compression also caused the ID of the outer wheel to be enlarged? i need to remove one of the wheels that wasnt having the issue and see if it is more of a pressure fit

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Bad
The Delrin that the V wheels are made from is a very dense plastic and I doubt if it got compressed. My bet is after measuring all of the wheels I received that your wheel was just not machined correctly at the factory. The ridge in the center is undersized and the washer is over sized and the ID of the wheel is out of spec. The bearings are also undersized.
This all lead to the wheel moving on the bearings as you showed in your video.

Dave