The new Powerbit ranges are meant to serve as a more compact and versatile verision of the previous models.
The new Powerbit ST58 (89-115 mm) and ST68 (102-140 mm) for underground drilling have all the same characteristics of the successful Powerbit T45 and T51. But Atlas Copco have optimised the bit shape, and opted to make the body steel harder and stronger. The patented Enduro Extra button surface treatment technology and Trubbnos button shape, were added for improving strength and wear resistance.
The ST thread and Powerbit ST58 and ST68 are built for long and straight holes, and some models are available with optional short guide wings. This minimises hole deviation and makes sure that the bit body wears at the same rate as the buttons, decreasing the risk for the bit to get stuck in the hole. The thread and undercut are also optimised to reduce strain and minimise the risk for material fatigue.