Shaftment

Some hand-based measurements, including the shaftment (1)

The shaftment is an obsolete unit of length defined since the 12th century as 6 inches, which nowadays is exactly 152.4 mm. A shaftment was traditionally the width of the fist and outstretched thumb. The lengths of poles, staves, etc. can be easily measured by grasping the bottom of the staff with thumb extended and repeating such hand over hand grips along the length of the staff.