Made to the same dimensions as No.150 drills, these blanks are taken from the drill manufacturing process
and are finish ground to the same tolerance as the drills (ISO h8). They also have drill hardness
(HR ‘c’ = 62-64) all over and can be used as gauges, drifts, spindles, punches, locating pins and tool blanks.
They may have squared-off ends or spindle (coned) ends according to diameter, or the manufacturing
process from which they are drawn.