We have noticed over the years that some hammer users do not replace a leaking Cylinder Head Gasket on Single Acting Hammers. They do this on the assumption that it really isn’t necessary because a Single Acting Hammer does not have pressure between the Cylinder Head and the Piston. It is true that on Single Acting Hammers air or steam is not directed into this area as is done on Differential Hammers. But when the Piston of a Single Acting Hammer Is on the upstroke the Piston travels up past the Exhaust Ports and traps air between the Cylinder Head and the Piston. This trapped air acts as a cushion to slow up and stop the upward travel of the Piston and Ram. Without the Cylinder Head Gasket the trapped air will escape and the Piston will strike the Cylinder Heed. Eventually this pounding will lengthen or strip the threads of the Cylinder Head Studs. This will allow more air to escape until the Piston will strike the Cylinder Head on every stroke and will break the Cylinder Studs and tear the Cylinder Head completely from the Hammer.