I used one if these. It was about two inches long.
Drill America - D/ASTCO31P12 #31 Cobalt Heavy Duty Split Point Stub Drill Bit (Pack of 12), D/ASTCO Series https://www.amazon.com/dp/B00FX9TZMM/ref=cm_sw_r_cp_api_glt_fabc_CBM9JTBNH1X39DC3SH2G?_encoding=UTF8&psc=1