Drag Bits admin March 17, 2015 Construction Tools Size (Inch) Thread (Pin) 4 7/8 – 6 1/4 2 3/8” API 6 7/8 – 12 ¼ 3 ½ API 7 7/8 – 12 ¼ ½ API ← Coupling Sleeves Rock Roller Bits →