I mainly use a 3/8 head tap for cleaning threads. even try to work. However, the durable metal alloy fails. It would be a great advantage if the manufacturers could deal with tolerances rather than the rough tolerances obtained in casting. Maybe do some CNC finishing and improve the handle design? In general I wish the 22mm drive O2 1/2 head wasn't star shaped as more angles result in more wear points; whereas the square has a large surface that grips the anvils of hand ratchets.