VALYRIANTOOL 1/4" Cobalt Drill Bits(20PCS), M35 HSSCO High Speed Steel Jobber Length Twist Drill Bit Set for Hardened Metal, Stainless Steel, Cast Iron, Plastic and Wood

Why Choose from us? This drill bit contains 5% Cobalt (M35 Cobalt HSS), which increases the strength, the tool life and makes it more heat-resistant. Rockwell Hardness >= 67. 135° Split Point with straight shank prevents walking and makes drilling precise. Fully Ground spiral groove design clears particles quickly, decreases friction and heat for a faster and cooler drilling performance. Drilling Notice: Keep the drill bits vertical to the object when drilling. Be sure to make both bit and work piece stable. Tilted bit is prone to break. When using bits with a power drill, it's recommended to use them with low speed and drilling pressure. The thicker the bits is, the slower speed and pressure should be taken. Friction will accumulate heat between bits and work piece. Be aware of the heat, add water or coolant if necessary. To avoid breaking, 1/16" and smaller bits are suggested to be used with a pin vise. Thick metals are recommended to be drilled with drill press, which is more stable, and adjustable. To have the best performance, you shouldn't drill deeper than 1/2" of the drill bits' flute length.