Sorry I meant the heater, I just want to look for a nice wood handle and wasn’t too sure how it detachedBowl handle? The handle likely uses a standard thread pitch. You could take it to a local big box hardware store, find the "thread finder" display, and see what matches. Then you'll have the dimensions you need for buying or making a replacement.
Or do you mean the handle on the heater? That's a slip fit affair, I believe.