What type of drill bit is strongest for drilling holes on hard metals such as harderned steel? - Quora
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7.6mm 7.7mm 7.8mm 7.9mm 8mm 200mm Length Extra Long Metal Wood Al Plastic High Speed Steel Hss Straight Shank Twist Drill Bit - Drill Bit - AliExpress
![DEWALT 3/16-in 3-3/4-in Cobalt Alloy Steel Twist Drill Bit in the Twist Drill Bits department at Lowes.com DEWALT 3/16-in 3-3/4-in Cobalt Alloy Steel Twist Drill Bit in the Twist Drill Bits department at Lowes.com](https://mobileimages.lowes.com/productimages/066661d6-c6c8-47e2-afc2-4bb1235d63ed/00252101.jpg?size=mpdhi)
DEWALT 3/16-in 3-3/4-in Cobalt Alloy Steel Twist Drill Bit in the Twist Drill Bits department at Lowes.com
![LWCUSNJ M42 8% Cobalt Drill Bit Set,19pcs Industrial Titanium Coated HSS Metric Drill Bits for Hardened Steel,Metal, Cast Iron, Wood and Plastic (1mm-10mm) - Amazon.com LWCUSNJ M42 8% Cobalt Drill Bit Set,19pcs Industrial Titanium Coated HSS Metric Drill Bits for Hardened Steel,Metal, Cast Iron, Wood and Plastic (1mm-10mm) - Amazon.com](https://m.media-amazon.com/images/I/71rDSBERs4L._AC_UF350,350_QL80_.jpg)