Oiling the Bearings of the Rotary Valve
Valves should be oiled every two or three months. This can be done on most types of rotary valves without disassembling the entire valve or removing the string. First loosen stop arm retaining screw about 3 or 4 turns, as at (1) in view A. Then unscrew valve cap completely. Next, with a screw driver wood handle or similar piece of wood, tap the head of the retaining screw. This will push the rotor toward the back of the valve and will force out the valve back head. You will find the retaining screw now rests against the stop arm hub. With your finger, push the rotor toward the front again. This exposes a part of the rotor shaft at (2) in view B. A drop of fine machine oil should be placed here. Valve oil is recommended for this purpose. The oil will run down the shaft to the bearing in the valve front head, if the horn is held in proper position. Another drop should be placed inside the bearing of the back head and on the short shaft bearing. Don’t use an excessive amount of oil, as too much oil is just about as bad as not enough.
This method of oiling applies to valves, in which the rotor is suspended at two bearing points but it does not apply to the type of valve in which the sidewall of the rotor is in contact with the sidewall of the casing. In this type of valve, the rotor itself is a sort of bearing and requires oiling. Obviously oil applied by method outlined above will not reach the sidewall of the rotor. To oil the rotor itself, drop oil between the casing and the rotor. Do this from the back side when the rotor is pushed toward the back; this allows considerable clearance for the oil to run down.
After oiling, the back head should be replaced. View A, the mark on the valve casing (1) and the mark on the edge of the back head (2) should be in line. To seat the back head, use a wood tube with a hole somewhat larger than the diameter of the shaft and bearing in the center of the back head; possibly a bamboo fishing pole section would be the easiest to secure. Place the back head firmly in proper position and with the wood tube and a small hammer or mallet, tap gently until it is securely seated. Then screw the valve cap back on and tighten the stop arm hub retaining screw. Wipe off any excess oil.