Abstract: A bolt on drive assembly for a core drill which utilizes a spoked reinforcer mounted between a pair of discs. The discs are removably mounted on the tube by bolt fasteners. A drive connection is removably mounted and centrally located on a outer disc of the pair of discs. The drive connection is adapted to connect with a drive shaft to cause rotation of the tube.

Abstract: Slotted saw blades are shown with wide slots in which hardface inserts extend below the bottoms of the slots and interlock with the core, extend above the periphery of the core, and extend at a negative hook angle for the direction of core rotation. In various embodiments, the inserts, which are bonded to the core, include elements that are integral portions of the cutting segments, elements arranged in each slot so that one is at the negative hook angle for one direction of core rotation and the other is at the negative hook angle for the opposite direction of core rotation, and wedge shaped elements.