A connector block and associated locking setscrew for an implantable electronic
tissue stimulating device are designed to eliminate thread damage to the setscrew
which is a cause of the setscrew becoming stuck in the connector block. The threaded
bore in the connector that is adapted to receive the setscrew is provided with
an undercut at the end of the threaded bore where the undercut provides an annular,
360-degree flat surface that is normal to the longitudinal axis of the setscrew
receiving bore. The setscrew employed is designed to have a shoulder machined a
predetermined distance below the terminus of the final thread by machining a reduced
diameter portion on the distal end of the setscrew. Now, when the setscrew is inserted
into its threaded bore, the shoulder on the setscrew and the flat surface on the
undercut in the connector block meet, preventing any portion of the screw threads
from extending beyond the internal threads formed in the setscrew receiving bore
of the connector block.