Magnet wheel for XRP robot

I always thought the battle robots using magnets on their wheels or treads to hold them to the ground were a great idea. I don't know how useful this would be to people's use of the XRP robot, but maybe it will be of use to you. Or maybe you want to build a version that will climb up your refrigerator. 

I used 4mm diameter, 2mm thick magnets for this, because that's what fit in the original wheel thickness. I don't know how well that will work with the weight of the standard robot. With modifications, you could do two bands of 4mm magnets, or larger diameter magnets, for a stronger hold. 

You will need 39 magnets, 4mm ø x 2mm, PER WHEEL, so 78 for a two-wheeled robot. I bought mine from Super Magnet Man. You will also need cyanoacrylate super glue, and something hard to push the magnets into place.

I have provided two versions. I printed the plain one first, and found it tedious to clean out the holes for the magnets, because the walls between them printed imperfectly, and tended to break or get in the way. The second version (which have “cutaway” in the title) should solve this, at the cost of a little less area for gluing.

I recommend inserting every other magnet around the circle, so that they don't misbehave and pull up their neighbors before the glue dries. Use a very small amount of super glue in the bottom of the hole. It is best to use a stack of the magnets to press each one into place, then carefully hold it down with a thumbnail or a piece of plastic or wood while you slide the stack off to the side. Then press the magnet in to seat it. If there is any extra glue seeping out, try to clean it off before moving on, or it's likely to stick your fingers to the wheel. I found it best to hold down the nearest magnets already in the wheel when bringing in each new one, so as not to pull half-dry ones out with the force of the stack.

I assume it is best to have all the magnets oriented the same way, with, say, their North ends pointing outwards. To keep track of this, you can always just briefly touch your stack of magnets to a previously inserted one.

My entry in the Experiential Robotics contest, June 2024, based on the wheel published by @Experiential_1229651 in this model.

This is a modification of the original wheel ("Wheel Bigger Bore"), replacing the o-ring tire groove with 39 cylindrical slots for disc magnets.