8mm straight D-bit reamer

grabcad

This is a little D-bit I made to ream the valve chest for a steam engine I'm building from a CAD model by Nico. It's made of silver steel (also known as drill rod), left dead hard, and the valve chest it was used to ream (seen in the photos) is stainless steel (304 I'm told). Despite this being quite a tough material to machine, this little reamer still cut nice and freely, so I'm pleased to bits with how it turned out.