My school have currently rounded 2 omni wheels as those wheel have been used in many competition and it has been a long time. Is there anyway to make it workable again ?
I think you’re talking about the axle rounding out the would-be square hole in the center of the wheel.
You should be able to use a bar lock screwed through the holes on the wheel to recreate that square hole. You may have to drill holes to get the screws in the correct place so it doesn’t wobble. Other than that, I can’t think of any other ways to fix it except clamping it between gears or sprockets that have the square holes in-tact.
If you have some of the standard 4" wheels (non omni wheels) you can remove the axle inserts from them and put them into your omni wheels instead.
I don’t think the centres of omni wheels are inserts. I tried to take them out once to put metal ones in and I couldn’t. It would be really helpful if they were, though.
they are inserts. we took out a few and replaced them with the metal ones made for HS gears. but we only did it to one side of the wheel ( the omni wheel has inserts on both sides. )
Oh. I spent ages trying and only make an ugly-looking mess of the wheel :/. How did you do it?
some omni wheel inserts are loose but not possible to take out easily. what i do here is to insert a shaft halfway into the wheel, bend it such that the shaft is at an angle, and try to pull or pry it out from the inside.
for those which are not so easy, just use a very stong stick, probably a flat-blade screwdriver, and push the inner part of the insert out. this is difficult but possible. let the screwdriver enter from one side, and push the other insert out.
but we’ve only got like… 3 or 4 of these omni wheels
if it starts to get ugly, get out a drill 
it makes the job more fun too 
I think it was you guys who returned one of our omni wheels completely destroyed with a metal insert hammered into it actually…
I found it today