... history Milled Tooth Rock Roller Bits: 7 7/8 to 14 1/2 ModelTCI BIT, STEEL TOOTH BITIADC CODE 116 117 12 ... journal bearingaircooled bearing typeFormation or layer soft ,medium soft ,hard,medium hard,very hard formationButton size (extra features)Button bit,saw teeth1) Y ... -60187.3~241.37 3/8-9 1/2539-83360-40hardSandy, Shale, Quartzite, Hard Dolomite, Hard Sandstone etc.695.~-174.63 3/4 ...