Bench Drilling ST68

ST68, the drill string components feature an entirely new thread design. Compared with T51 rods, the 40% larger rod cross-section of the GT68 MF rods provides 65% higher bending stiffness and withstands the Impact-waves from the piston much longer. So much so that both drill-rod and shank adapter life can be doubled. As an extra bonus, the more rigid drill string permits optimum drilling patterns and higher rates of penetration.

Compared with other drilling tool systems, GT68 system permits a wider hole range using the same rock drill. Have been specially developed for use with modern hydraulic top hammers and are available in a similar range to the standard Drill Rods. Plus ST68 Thread on 87mm Round material.

It is common practice to bump up the drive end of drifting drill steel for added strength at the rock drill end to accommodate larger diameter and shank adapters. Drill steel of rock drilling tools is available in many standard lengths to match the drill feeds on a multitude of available drifting jumbos. A rock drill bit diameter closer to the steel diameter can be used since the coupling does not enter the hole, this enhances flushing and hole accuracy.

Male/Female (M/F) Steel

Male/Female drill steel provides more rigid connections and is easier to uncouple and handle. The service life also tends to be better than with separate couplings. This is fortunate because the coupling end cannot be replaced.

The advantages of drilling with M/F extension drill steel include: easy handling, quicker uncoupling, tighter connections and the potential to drill straighter holes. Used for both surface and underground applications on larger hydraulic top hammers, Prodrill’s Tubular Drill Rod System feature Drill Bits, Shank Adptors and Male/Female Tube Rods available in ST58 and ST68 Threads with bit diameters in the range 89mm-150mm(3 1/2”-6”),also available are Guide Tubes to assist in straight hole drilling on R32 through to T51 Threads, for holes in the size range 54mm to 115mm.

ST68 (2 3/4″)

Button bit ( ST68)	Dimensions (D)		Flushing hole (mm)		Buttons (mm)		Angle	Class	Part no.
	mm	inch	Front No size	Gauge No size	Front No size	Gauge No size
	102	4”	2×10	2×14	8×16	6×14	35°	H	30102ST6814
	115 127	4 1/2” 5”	—— ——	3×13 3×14	9×16 9×16	6×14 10×14	35° 35°	H H	30115ST68F15 30127ST68F19
	115 127	4 1/2” 5”	—— ——	3×13 3×14	9×16 9×16	6×14 9×14	35° 35°	M M	30115ST6815DR 30127ST6818DR
	115 127	4 1/2” 5”	—— ——	3×13 3×14	9×16 9×16	6×14 10×14	35° 35°	H H	30115ST6815R 30127ST6819R