Description of Uxcell Spade Paddle Woodworking Cutter
Size Included: 10mm/0.4"; 12mm/0.5"; 16mm/0.6"; 18mm/0.7"; 20mm/0.8"; 25mm/1". Total Length: 150mm/6"; Hex Shank Diameter: 6.3mm/ 0.25"(1/4"). Quick-Change hex shank with groove for reducing slipping and prevent falling off. Constructed from high speed steel for durability with Titanium coated surface for longevity. You can get 6 in 1 Set spade drill bits. Please keep the drill Vertical while drilling.
12mm for the recessed hinges I installed. NO raw edges on the outer edge. I spent a lot of time reshaping and sharpening a 12mm bit for my purpose. All I can say is they were cheap.
Pros
Manufactured from high speed steel for durability with titanium coating for durability.