Introduction

I have built a B-Robot as designed by jjrobots https://www.thingiverse.com/thing:2306541 I was happy with most of the parts (although I redesigned many pieces in OpenSCAD as I wanted to modify them) but I had problems with the wheels - it is very difficult to accurately print a D-profiled hole that will fit neatly onto a stepper motor's shaft. Because of this I decided to redesign the wheel in OpenSCAD, incorporating a nut and set-screw to lock the hub onto the shaft. Now it is possible to print the wheel, clear the hole with a 5mm drill bit, insert a square M3 nut and lock it all together with a suitable M3 screw. This has proved to be very effective and secure. I have also included a small hemispherical hub cover (which I used) and a more fancy one (which I didn't use as I preferred the look of the first one).

Printing

First, print the test hub to see if you will be able to insert your M3 nut - I used square nuts because (1) they are more secure and won't rotate, and (2) because I had some handy! If the hub works for you then you can print 2 wheels, clear all the holes, then print 2 hubs and glue them into the outer hole in the hub. I didn't use support when printing as it was very difficult to remove the waste from the M3 nut and screw holes.

Modifications, and generating your own STL files

I have tried to make it easy to vary sizes by adjusting the variables near the top of the code. Make the changes, compile and export the STL file. If you want to do this then you will require the following library: Chamfers Chamfer library (by 'SebiTimeWaster') - note that the file will need renaming to "chamfer.scad". Select the part you wish to compile and generate by commenting or uncommenting the appropriate lines at the end of the code - do just one piece at a time!

Future development

I intend to develop the basic wheel with the aim of fitting wider rims and TPU tyres - but I'm not quite there yet. Perhaps someone would like to do a remix in the meantime?

Found 6 3D-models for “b-robot” across many websites

Aggressor Bin for Harbor Freight Organizer (X-Wing TMG)

B-robot EVO2 bumper CUSTOMIZER

Display Stand for B-robot EVO 2

Alternative wheel for the B-Robot (OpenSCAD)

B-Robot Evo2 Bumper Remix

Kidbuild B-Robot