Wet Grinding for Valve Refacing
Page 43
If you've noticed an error in this article please click here to report it so we can fix it.
WHEN refacing valves by grinding, VI' it is undoubtedly of practical advantage to feed liquid on to the grinding wheel. By this means the work is kept cool, and distortion, dis coloration and loss of temper are prevented. Moreover, a better finish is imparted to the surface.
Appreciating this fact, Black and Decker, Ltd., Slough, has introduced a wet-grinding valve refacing machine, which speedily trues up burnt valves, imparting a truly cir cular face and a mirror finish. Driven from the headstock motor is a small gear-type pump which draws cooling liquid (a thin solution of oil and water) from a reservoir at the rear of the machine. A filter is provided to arrest metallic particles and grit.
From the pump the liquid is fed to the wheel guard, which is designed in such a way that only a thin film of liquid covers the periphery of the wheel. A detachable lip picks up all surplus fluid and directs it back to the reservoir without wastage.
A not unimportant point is that in wet grinding the rate of cutting speed is of less importance than in dry.