There are many types of rock drilling tools, drill rod is one of them. It is connected with the rock drill bit and used with the rock drill to drill in rock or rocky soil. There are many types of drill rods. With respect to the connection mode between drill rod and rock drill, there are shanks with cones, forged shoulder shanks or no shoulder hexagonal shank, and threaded shank connections with ear wings. With respect to connection between drill rods and rock drill bit, there are several types of drill rods such as tapered drill rods, threaded drill rods, and cemented carbide integral drill rods. As the tapered drill rod is the most widely used one among all types of drill rods, it occupies a proportion of all rock drilling tools. Therefore, today we mainly share with you the types of tapered drill rods.
What is a tapered drill rod?
Tapered drill rod is a hexagonal hollow rod with a shank, the shank is connected to the rock drilling equipment and the rod end is tapered, which can be connected to the tapered drill bit.
Types of tapered drill rods
When connected with a rock drill, the tapered drill rod adopts the forging shoulder shank. When connected with a rock drill bit, the cone structure is adopted. The hollow hexagonal tapered drill rod is a small section drill rod. Internationally, The more common hollow hexagonal tapered drill rods are 19, 22, 25, and 28 mm.
1. B19mm drill rod: 19mm means across flats width of hex rod, the length of the shank end is 108mm, that is, B19*108mm.
2. B22mm drill rod: B22*108mm and B22*82.5mm.
3. B25mm drill rod: B25*159mm and B25*108mm.
4. B28mm drill rod: B28*159mm.
In the drilling, the tapered drill rod is subjected to impact, torsion, and bending stress at the same time, but it is mainly axial impact stress. Since the drill rod is slender, the bending stress generated in drilling is also very harmful. Therefore, the requirements for the operating procedures and quality of the drill rod will be relatively high. The quality of the tapered drill rod is mainly related to the quality of the brazing steel and smelting, but whether the manufacturing process is reasonable and whether the forging equipment is advanced and well-equipped is also extremely important.