https://omegatec.com/21cojo-jobber-drill-m-42-cobalt-135-degree-split-point-nas907-type-j.aspx
#21COJO Jobber Drill, M-42 Cobalt, 135 Degree Split Point, Size: #21, NAS907 Type J
#21COJO Jobber Drill, M-42 Cobalt, 135 Degree Split Point, Size: #21, NAS907 Type J. Size: #21 Decimal: 0.1590''