Brace shanks have a tapered square profile, which most toolholders grasp efficiently and without slipping as much as round shanks.
File handle shanks, used in hand-reaming, are rounded and fit the hand much like the handle of a screwdriver.
Morse taper shanks are tapered from one end to another. They fit into tool holders with the same taper. They allow efficient transmission of torque to the reamer and provide accurate, centered placement in the tool holder. A tang at the end of the taper is used to eject the reamer by pushing a drift-pin into the slot, which pushes the shank down and out.
Round shanks are the most common reamer shank. They are usually the same size as the reamer cutting diameter. This style fits into the widest range of tool holders.
Round handle shanks, used in hand-reaming, are cylindrical and fit the hand like the handle of a screwdriver.
Round with square end shanks have a round shank with a square end. They are usually the same size as the reamer’s cutting diameter. The square end helps reduce slippage and provides a secure fit in the tool holder. This style fits toolholders more securely than a shank without flats.
T-handle shanks used in hand-reaming, provide increased leverage when operating the tool by hand. The T-handle requires less effort to create the same torque as a file handle.