Spotting Drill Sizes

Automatic Drilling Unit, Gang Drills, Multiple Spindle Gang Drill

Spotting or Centering Drills are designed for centering work, making a starting hole for a larger drill and for chamfering. The short flute and overall length of these type drills is very rigid to ensure precise spotting prior to drilling. Use as large a drill diameter as is reasonable for the best results.

Size Decimal Equiv. Flute Length inch Overall Length inch
1/8 .125 3/8 1-1/4
3/16 .1875 1/2 1-3/8
1/4 .250 5/8 1-1/2
5/16 .3125 5/8 1-1/2
3/8 .375 1 2
7/16 .4375 1 2
1/2 .500 1 2
9/16 .5625 1 2
5/8 .625 1-1/8 2-1/4
3/4 .750 1-1/8 2-1/4
7/8 .875 1-1/4 2-1/2
1 1.000 1-1/4 2-1/2
1-1/4 1.250 2 4
1-1/2 1.500 2-1/2 5
1-3/4 1.750 2-3/4 5-1/2