Can I put a sprocket made for a keyed shaft on a D bore?

Naio wrote:
This is for my shave ice machine.

LOL

I would wait for the right stuff but if you must use the available parts I would look at running at reduced power if you can.

I doubt there would be any damage except to the mismatched sprocket and shaft. Unless that chain comes off and there is continued momentum in the secondary sprocket causing the chain to jamb or tangle on something.

If this is all temporary consider just having it welded on.