Product Description
The T38, T45, and T51 jumbo-bit family is intended for tunnel boring support holes, development rounds, and mechanized mining where threaded top-hammer equipment is used. The nominal thread series spans roughly 38–51 mm, or 1.50–2.01 inches, but the source does not give the corresponding hole gauges. Review the task through the construction drilling application archive and the ground through the hard formation archive. It is not a tunnel-boring-machine cutter or a guarantee against binding.
The source describes high wear resistance and “non-sticking” behavior with T38, T45, and T51 connections. This record treats those phrases as intended design characteristics, not measured performance promises. The construction is a threaded alloy-steel jumbo bit with fixed carbide buttons. Hole diameter, face profile, retrac skirt, button count, and flushing-hole arrangement are not provided. Binding depends on hole condition, cuttings removal, gauge wear, alignment, and rod handling, so no bit can be represented as immune to sticking under all tunnel conditions.
Use 1,000–3,000 lbf/in of actual diameter and 25–60 RPM after the selected thread and hole gauge are confirmed. Hard and abrasive formations are appropriate; fractured zones or poor flushing can increase jamming risk despite the source wording. Monitor pullback torque because cuttings buildup can mimic a geometry problem. Flow remains blank because thread series alone does not define rod bore or required return velocity. The limitation is the missing diameter-to-thread matrix and absence of a verified anti-binding test. Rock-mechanics concepts can be reviewed through the ScienceDirect engineering topics. Measure gauge after every trial.
