V-slot Wheel Bearing Extractor

Once upon a time i was fixing my 3d printer and the poor thing had a faulty v-slot wheel bearing. That wheel had a plastic wheel, a washer and two bearings, one of them was broken. One option to fix the printer was to replace the whole bearing (that was what most of the people were doing) but i thought it was a big waste of resources so i looked in the internet for a tool to help me fix the wheel extracting the broken bearing but the methods that I found were very ineffective and violent so I had no option but to design a tool to do the job. My idea was to design a tool with the minimum parts needed; in the end it was made with 3 printed parts. 2 pieces were printed in place, interlocked so that no glue is needed (the main part), a knob , it also needs some washers, nuts and a screw. I used fusion 360 for the design, cura to slice the model and a creality 3d printer.

The first design was for the v-slot wheels with 625zz bearings. After that i complemented the design with a model to extract also the bearings of the smaller v-slot wheels that use MR105zz bearing (10mm outside with 5mm bore).

materials needed:

• v-slot wheel bearing to fix
• two nuts M2.5
• two open washers (outside diameter 5mm, inside diameter aprox 4.5mm)
• one M2.5 screw
• 3d printed parts (2 parts : main part and knob)

tools needed:

• screw driver with H1.5 bit

I printed 3 parts with no rafts, supports everywhere, layer resolution 0.2, infill 35% using PLA filament. In the images you can see the model formed by 3 parts: the knob, a yellow part and a red part. Both the red part and the yellow part are interlocked and printed in place as a single part.

Once that both parts are printed, the main module has two interlocked pieces that get printed together. It is necessary to unlock them to get it working. A small pressure in the inside of the cilinder will break the bonds and allow free movement of the two elements (they stay interlocked). To break the bonds it can be used a small flat surface to make some pressure in the inside, there are 3 supports inside 120 degrees apart from each other. A click can be heard applying some pressure on each of the 3 supports and the inside piece will be free but still interlocked.

The screw with both washers goes in the inside hole, one nut in the outside of the main part and another nut in the knob. Then attach the knob to the screw.

The idea of using this tool is to separate the bearings from the whole wheel without damaging neither the wheel nor the bearing so you can replace the broken bearing and get the wheel in working condition.

To do that, the wheel is fixed in the inside of the tool tightening the screw so that the washers expand and block the bearing. After that the knob can be turned and it will press the pusher over the wheel plastic leaving the bearing attached to the tool. Then unscrew the broken bearing and replace it with a new one.