>>6849470If you don't care about the pieces, I'd try sanding out left's neck as you said.
If you think it's too short, you could try pic related. Would require a pin vise/dremel to drill out the whole to fit the plastic cylinder.
A similar option would be to buy a joint set or get a joint from somewhere to use as a new neck, cut off left's neck, pin vise/dremel hole to fit joint, fill the body's hole with putty, pin vise/dremel to fit the joint.
