$51.99 Step Drill Bit Double-Fluted #1, 1/8 to 1/2-Inch - KTSB01 | Klein Tools - For Professionals 
IDEAL 1/8 in.- 1/2 in. Step Drill Bit in the Step Drill Bits department at Lowes.com
K Tool International KTI71236 3/16-1/2 Step Drill Bit (EA) | eBay
