Based on manual surface grinder, it covert the longitudinal and vertical machine to fully automatic The bidirectional friction electronic clutch, simple and reliable structure, clutch reversing process has no impact, no noise, safe commutation 5000000 times; the electric control part with electronic switching frequency switching, The service life 10 times longer than the relay control, simple operation, sensitive, infinitely variable; large output torque, low noise, Safe and reliable. Power supply use a number of mechanical and electrical protection function which is safe voltage, Energy saving, power saving, power consumption per class (calculated according to 8 hours) is only 0.6.When the manual grinding is working, before and after the workbench's movement, in and out, around the reversing are automatic operation, greatly improving the production’s efficiency and the surface finish, suitable scope that from the original single, small batch to mass batch.