Makertech Proforge 3 Rubber Foot Helper

thingiverse

Here's a simple part to assist in mounting the molded rubber feet to the base of the Proforge 3 printer, and also to help them function in a more robust fashion. By default, the supplied feet have molded cavities which are designed to accept an M4 nyloc hex nuts, but the problem is that the nuts fit quite loosely, and even if the fit was a lot tighter, the rubber simply deforms when you attempt to put enough torque on the mating bolts to get them to engage the nylon lock ring. You end up trying to hold the nut with needle-nosed pliers, which is very slow and frustrating. Another potential issue is that if the foot experiences significant side-load stresses (vectors parallel to the machine base, like what would happen if you pushed the printer over a grippy surface that developed a lot of friction with the rubber), concentrated forces could eventually cause the rubber to tear where it develops stress raisers in the thinner areas around the nuts. This part mitigates both issues. First, it acts as a sort of washer that prevents circular movement when tightening the nuts, because the two captured hex posts lock it into place. Second, it distributes mounting and normal use stresses across a very large surface of the foot, instead of allowing them to concentrate in two spots. To mount these parts, first press in the nyloc nuts, one at a time, by resting one against its capture cavity and then pushing the printed part against a desktop or some other flat surface. Next, press the protruding hex columns into the mating cavities in the rubber feet. You're now ready to mount the augmented feet. *NOTE:* you must use longer M4 screws than what are provided in the kit; I used M4 x 22mm, though you could also use a 21mm or possibly even a 20mm. In practice, using these "helpers" made the rubber feet installation very quick and easy. One caveat: I've only just begun to assemble my printer, and I immediately stopped to design and make these parts after getting frustrated with the very first step. I can see there are voids in the sheet metal base that might be partially occluded by the increased dimensions of the foot assembly, so it might be wise to install these modified feet later, instead of right at the beginning. I printed these parts on my Prusa I3 MK3S in PETG with 100% infill. I'd imagine they would be equally successful when printed from ABS, PLA, or any other reasonably rigid filament.