You can buy adjustable reamers that will cover this hole size, they are made to cover overlapping hole sizes from small to large dia. Just get one that covers your requirements, adjust it using a mic or vernier and your ready to ream. Try to use it on some form of fixture to hold the reamer as you turn it....a lathe or stand drill works great...if not just use by hand and take your time...keep checking alignment with a square untill your are through.
Ian |