What's That Funny Looking Cover on my Boring Head?

Glad you asked – It’s an oil port. BIG KAISER finish boring heads from BIG DAISHOWA can easily be serviced by you, the customer, to ensure smooth reliable performance for many years. With the lubrication gun 10.692.404A filled with any standard light machine oil, the boring head can be serviced by rotating the diameter adjusting screw in the positive direction until the cartridge reaches the positive range stop. Oil can then be pumped into the boring head through the oil port. Once the head is full, range the cartridge back to the negative range stop, and inspect the oil that is forced out around the dial. If it is clean, congratulations, you can put the boring head back into service! If not, perform the previous steps another time.