Any good hardware store should have a reamer that size or on-line at http://www.use-enco.com . If you don't have a drill bit set, you will also need a 27/64 drill bit to provide the starting hole for the reamer as it is not tapered. I don't think you'll split the wood if you work your way up to the final size in several steps with different drill bits. Double check the 7/16 but it sounds right - I did it for a friend who has a BME.