Standing Desk Monitor Wheel

With the transition back to school, I decided to improve my desk setup with an adjustable sit-stand desk frame, to improve the ergonomic situation and make those long evenings working behind the screen a bit more enjoyable. Studying at the Catholic University of Louvain in Belgium, we get a lot of group work to do, so Team calls are quite frequent as well.

The only problem with that new desk setup is the fact that when my arm-mounted monitor is pushed back, it will grind against the wall when the desk is moving, leaving an ugly streak of paint on the wall.

So I decided to take the time to design a small accessory, that will mount to the monitor arm and hold a rubber rollerblading wheel, to act as a bumper/roller and prevent the monitor arm from coming in contact with the wall.

As the accessory we are making will have to match some dimensions of real-world objects, we first have to take precise measurements of the arm and the rollerblade wheel. That will allow us to design a piece that matches the closest real-world objects it will come in contact with, as well as allow for the best optimization possible.

We need to make a piece that allows the arm to go the furthest back possible while making sure the wheel touches the wall before the arm. So the contact point between the arm and the rollerblade wheel shaft will be crucial, to make the whole thing work.

To find the right distance, I made a quick schematic of the situation.

With a wheel dimension of 64 mm and an arm dimension of 31 mm, that gives us (64/2 - 31/2 =) 16.5 mm for the distance that the shaft needs to be off-axis, in order to have the wheel and the arm touch the wall at the same time. Bringing the axis closer to the wall by 5 mm will give us a tiny margin, making sure that the arm isn't touching the wall.

Once I had all the measurements, I jumped into Fusion 360 to model everything.

The process was fairly straightforward. Fusion works by drawing 2D shapes on a plan, and then extracting or removing them to manipulate the matter.

To make sure all the pieces fit, I added 0.5 mm (1/64 inch) to all holes while modeling.

I also added a small bump where the ball bearing gets in contact with the 3D printed part, to avoid the rollerblade wheel from rubbing against the 3D print.

In the next step, we will add a grub screw to the side of the ring, to prevent it from spinning around the monitor arm. I didn't add it in the modeling process, as I wanted to make sure the ring is printed out as solid as possible.

For the print settings, I used PLA with 100% infill.

As the grub screw used to maintain the 3D-printed ring in place is fairly small (M2.5), there are chances that the plastic threads won't be strong enough to prevent the screw from moving. To anchor the small screw better in the 3D print, we can use a heat set insert.

You first need a hole that's a tiny bit smaller than the insert.

Then, you need to heat up the insert with a soldering iron or a flame and push it into the 3D-printed part in a straight line. To prevent the melted plastic from plugging up the hole, you can thread a screw into the insert, before pushing it in.

Once the insert is in place, leave it to cool down, making sure not to wiggle it around the soft printed plastic.

Just like that, we now have a strong threaded hole, that will have more grip on the grub screw, making sure it will stay in place.

To mount the rollerblade wheel, I found out that the inner dimension of the ball bearing is slightly smaller than the head of the 12 mm 5M bolt I was using. So I didn't have to 3D print any shafts, as I could just force the bolt in the ball bearing backward, giving quite a solid connection.

The shaft won't have to bear any substantial axial forces, so screwing the M5 bolt directly into the 3D print will do just fine.

We can now remove the monitor from the arm and secure our new accessory in place with the grub screw. After popping the rollerblade wheel on the shaft, we can put the monitor back on the arm.

To clean any markings that the unupgraded arm has left on the wall on the wall, a magic sponge can be used.

And here we have it! A functional guide wheel that took a few hours to make, but will save us a lot of headache when handling the monitor arm.

This Instructable used the dimensions for the real-world items I had on hand, but of course, you can easily adapt this project to your desk setup by changing the dimensions. The rollerblade wheel could also be replaced with a 3D-printed TPU wheel, to keep the cost lower.

Thank you for reading my Instructable, and have a great day!