HYMNORQ M35 40-Piece Cobalt Drill Bit Set 3/64 to 3/32

Precision Cobalt Drill Bit Set

The HYMNORQ M35 set supplies 40 cobalt-alloy twist bits in the four smallest fractional sizes most used for detail work in stainless steel, high-carbon steel and cast iron. Machinists, gunsmiths and model engineers who break tiny bits regularly will appreciate having ten spares of each diameter on hand. M35 grade steel with five percent cobalt delivers a Rockwell hardness of 65-67 HRC for heat resistance that standard high-speed steel cannot match.

Limits of Small-Diameter Drilling

Bits at 3/64, 1/16, 5/64 and 3/32 inch are inherently fragile; cobalt content improves wear life but does not eliminate breakage from side loads or misalignment. The 118-degree chisel point offers better tip strength than sharper angles, yet still requires steady feed pressure and rigid workpiece clamping to survive. Fully ground flutes clear chips faster than roll-forged equivalents, reducing the overheating that accelerates dulling in deep holes.

The Specification That Decides Fit

This set covers only the four smallest fractional sizes between 3/64 and 3/32 inch; any job requiring larger diameters or metric dimensions will need a different assortment. Buyers who need a broader range of inch sizes, metric steps, or bits for wood and plastic should look elsewhere. The 40-piece count is split evenly across the four sizes, so inventory depth is fixed at ten per diameter.