Boring jig apparatus

A jig used for precision boring of holes in a working surface of an elongate work piece, said jig comprising

• a pair of mounting plates;
• means for connecting the mounting plates together in adjustable, spaced positions such that the mounting plates face each other and can be moved in a direction toward and away from each other;
• engagement pad members attached to mutually respective, bottom sides of said pair of mounting plates, said pad members being adapted to engage opposite sides of a work piece in firm engagement therebetween when the pair of mounting plates are moved toward each other, with the work piece being disengaged when the pair of mounting plates are moved away from each other;
• a guide member having means for guiding a boring tool in a linear movement toward and away from a working face of said work piece, said guide member comprising a support plate and an associated guide block, with said support plate being mounted between said pair of mounting plates and said guide block having an elongate bore therethrough which acts as a guidance bearing for a rotatable shaft of a boring tool such that the shaft can be moved back and forth within said bore in the guide block to move the boring tool toward and away from said work piece;
• and
• means for mounting said guide block to said support plate in a position between said pair of mounting plates such that the linear movement of the boring tool lies in a plane passing generally through the longitudinal axis of said work piece, said means for mounting said guide block to said support plate comprising an arcuate track means on said support plate and attachment means which connect said guide block to said track means for arcuate movement of said guide block along said track means, with said track means being formed by an open slot in said support plate and said attachment means comprising a pair of spaced pins extending from said guide block into the open slot for translational movement along said slot, such that the angle between the direction of linear movement of the boring tool and the longitudinal axis of said work piece can be selectively varied.