Endpin jack reamer, 3-12mm

Two-step reamers are best if you often need to ream out for endpin strapjacks. However, for occasional use a cheaper option will often do, as you just need a neat 12mm (1/2") diameter hole. This is a reliable alternative, made from high quality heat-treated carbon steel. It can be turned by hand or run slowly in an electric drill. As well as allowing you open out the hole gradually, it has a long enough shank to allow you to make a 12mm hole through the full thickness of the endblock on most guitars.