Abstract: A hole groover comprising a pair of grooving bits radially protruding from the surface of a drill rod and connected to swivel upwardly and downwardly near the end of the drill rod where the drill bit is connected. A connecting rod is connected to the inside ends of the groove bits and causes arcuate movement of the grooving bits as it reciprocates. The hole groover further includes a gear box which is connectable to a rotary drilling unit which converts rotational movement of the rotary drill until to reciprocating movement of a lever. The lever is connected to the connecting rod which causes movement of the grooving bits. The device is readily adaptable to be connected to most rotary drill units and the depth and intervals of the grooves can be easily controlled by adjusting the length of the grooving bits and the gear ratios. The device enables grooves to be cut in a wall hole surface, concurrently with the drilling of the hole.

Abstract: A borehole stress-meter includes a resiliently radially expandable hollow body within which can be positioned a gage plug having strain gages fixed thereto. The interior section of the hollow body is tapered, as is the gage plug so that advancement of the gage plug within the hollow body will cause the gage plug to become prestressed. The hollow body can be inserted into a bore drilled in earth material whose stress is to be measured by an installation or setting tool. Subsequently, the gage plug is advanced within the hollow body so as to prestress the gage plug. The setting tool is then removed and stress may be measured by an appropriate strain indicator.