Review on CTH4000 Carbide Tipped Carbide Drill by Drill America by Charles Barney

This is by far the best hole saw I have owned in the last 50 years. The only drawback is the quality control. ONE!] hole the set screw fell out. At least the screw kindly waited for the drill to stop. So be sure to check the set screws before use. I drilled a small reset onto the shaft so the set screw doesn't just sit on a flat surface. Then tighten both screws as tight as possible. more than 10 holes drilled with 0 [ZERO] problems. Hence it gets a 5 star rating, unlike other carbide tipped bits that only see a few uses. I cut 3/8" sheet steel and couldn't be happier.