It is attached to a brass disk E, which is fastened to the centre of the diaphragm F by means of a rivet, and is capable of moving to and fro like a plunger when the diaphragm vibrates.
In 1229 the Order began the conquest of Prussia, founding fortresses at each step to rivet its conquests (for instance, at Thorn, named after Toron in Palestine), much as the AngloNormans had done in their conquest of Wales.
There is usually fixed above the sucker a short iron valverod, with a device known as a rivet-catcher to prevent damage to the pump by the dropping of rivets from the pump-rods.
With medium or moderately hard steel all rivet holes should be drilled, or punched e in.
Less in diameter than the rivet and reamed out, so as to remove the ring of material strained by the punch.