depends on how you want it converted...
If you are not willing to add a handle or extra piece of wood to the back, it is difficult to find one fat enough for a standard joint.
If you don't mind adding a handle, that then pushes the points up the forearm, you have lots of options.
ex.
1. No handle added, Notice the low points and length of forearm.
2. Handle added, notice how far up the forearm the points are.