Review on 🔧 AccusizeTools High Speed Steel (HSS) Straight Shank Counterbore 508S 0007 by Elvis Bragg

I wanted to add some 1/4"-20x1" cap screws to an aluminum part. The #10 countersink only picked up the pilot hole, not the countersunk hole which was too small in diameter to accommodate the cap screw. I had to use a 1/4" countersunk head to open the hole to allow the head of the aluminum cap screw to dig into the aluminum surface. This operation should have only required 1 countersunk bit instead of using another to finish the job. These drill bits are not suitable for SAE socket head screws. So be careful and research the pilot and countersunk hole diameters before purchasing. The quality was good and left a clean smooth hole.