The fuel cap for our older Eskimo ice auger was overtorqued, and the center was cracked and pushed out. Gluing it was more or less hopless due to the plastics used. 

It might fit other machines also as I suspect Eskimo did not make these themselves! If it fits your machnie, make a comment with what you fitted it to!

So I designed a cap that will go on top of the entire fuel cap. This is rather snug fit, and we filled it with some epoxy glue. The center is kept open to allow the cap to breathe using the original holes.

Remember that the diameter of the cap has increased, so you will be able to use more torque. It might be the fuel tank breaking the next time!

I have changed the text on top of the cap in the file. It now reads a warning about overtoquing the cap.

The smallest inside diameter is 43,9mm (1,728in or 1 91/125in).
The diameter of the outside "knobs" is 47,9mm (1,886in or 443/500in).