Chicago-Latrobe 69853 29PC 135 Degree Cobalt Screw Machine Drill Set

Cobalt Screw Machine Drill Set

This 29-piece set uses cobalt steel with a 135-degree split point for drilling hard metals such as stainless steel. The heavy-duty construction suits professional workshops and serious home users who need reliable performance on tough materials. It covers fractional inch sizes from 1/16 in to 1/2 in for a broad range of tasks.

Capacity and headroom

The 29 bits span sizes including 1/16 in, 1/8 in, 3/16 in, 1/4 in, 5/16 in, 3/8 in, 7/16 in and 1/2 in with many intermediate steps such as 11/64 in and 29/64 in. This range handles most common machine screw and clearance holes in metal. Very large diameter holes beyond 1/2 in or specialised tapping sizes are not covered.

Build quality and daily use

Cobalt alloy resists heat and wear better than standard high-speed steel during extended drilling sessions. The 135-degree split point reduces walking and starts holes cleanly without a centre punch. Bits are organised in a sturdy case that protects cutting edges and keeps sizes identifiable on the bench.