i remixed this to make it even better. 

i made it wider

i made the spring separate so it could be modified and replaced easy. and i made the base 1mm shallower so it would provide more spring distance. the original was harder to wind all the way up. it fits tight so it wont come loose when roller is not in place when changing tubes.

i removed the pads from the bottom so it wouldnt have to be printed vertically which makes it take longer to print. i instead made grooves to allow water to travel through.

i converted the shape to be able to solid model it easy. and put the .step in the files.

i changed the turnkey of the roller to a different design.

no supports needed