... tooth and tung , we can also produce the HA series ,HJ series ,FA series ,FJ series ,GA series ,GJ series and ... twelve, the size is 8-1/2”, 9-1/2”, 12-1/4”, 6”, 17-1/2”,4, the Rotary speed ... /2, 7-7/8, 9-7/8, 10-5/8, 12-1/4 Various sizes also can be made to order ... ,please do not hesitate to contact me.mob:86-15631707417 12 1/4'' oil drill bit