the T20 thread is designed to hold more securely and last longer than other screws

1/2-13 x 18 A307A Hex Bolt Plain Steel

Simpson Deck-Drive™ DSV WOOD Quik Guard® Coating screws offer superior corrosion protection in a self-tapping

The durable and lightweight tool features an adjustable pressure

1 1/4-7 x 6 Flat Socket Cap Screw Alloy

2" X 3" HSS Annular Cutter, Qualtech, Premium, DWC5-530-381 1 1/8-7 Socket Cap Screws Alloy the T20 thread is designedAnnular cutters are designed for fast, efficient hole making. Annular cutters cut only that material necessary to produce a quality hole. Works with Hougen Magnetic Drill, Milwaukee and similar machines.