Amazon.com: Irwin 10232 UniBit 3/16-Inch to 1/2-Inch 1/4-Inch ...
This item: Irwin 10232 UniBit 3/16-Inch to 1/2-Inch 1/4-Inch Shank Step Drill Bit by Irwin. In Stock. Ships from and sold by Bazaar51. $3.89 shipping.
http://www.amazon.com/Irwin-UniBit-16-Inch-2-Inch-4-Inch/dp/B00004THYY
Amazon.com: Vix-Bit 3VIXBIT Self Centering Pre-Drill Bit for 5/64 ...
Amazon.com: Vix-Bit 3VIXBIT Self Centering Pre-Drill Bit for 5/64-Inch Hinges and #2, #3, and #4 Screws: Home Improvement
http://www.amazon.com/Vix-Bit-3VIXBIT-Centering-Pre-Drill-64-Inch/dp/B0000224LF