A counterbore (4) surrounds the orifice.

The counterbore is filled with an explosive charge (43).

The first counterbore (68) is sized to receive valve packing (70) and the second counterbore (64) includes internal threads.

The assembly further includes a combination made up of an artificial tooth (49) having a bore (53) and a counterbore, and a metal insert (51) solid with the tooth and mounted within the counterbore.

The periphery of the counterbore is swaged to form an inwardly directed annular lip (154) securing the radial flange in the counterbore.

The biasing member is retained in a counterbore in the prism mount body, and an end of the machine screw protrudes from the counterbore.

The screw (20) comprises an axial bore (26) of circular cross section and a counterbore (28) of polygonal cross section.

A linear actuator comprises a motor having an output An end block is connected to a casing and to the motor and has a counterbore at a distal end with a bearing seated and retained in the counterbore.

The plug is then moved downward into the counterbore.

A self-centering seal (110) for a counterbore (150) with an inner passageway (152) and a counterbore (150) diameter (118) defining a recessed area (46) is described.

The seal assembly (10) requires minimal counterbore depth in the member in which the seal assembly (10) is mounted, and no modifications are required in the Belleville spring (50) or in the base of the counterbore.

A passage (5, 6) is provided which lies substantially in the plane of the plate and intersects the counterbore, and through which a flow of cleaning agent may be supplied to the counterbore, in order to flush ink from the surrounds of the orifice.

The nut body includes a threaded portion (22) and an unthreaded counterbore (24).

The second orifice layer (144) has at least one counterbore (146) formed therein.

A counterbore on the backing plate improves stress isolation properties of the sensor.