This post is copied from Need help with my new 10EE - post #223. It makes more sense to discuss this in its own topic.I'll discuss detail of the 10EE's rear bear section, including the labyrinth oil and how things have changed over time.
This is a section of drawing EE-99 (October 1941), showing the rear spindle bearing and LH clutch gear:
(This is a drawing that I color-coded several years back and have posted before.) The drawing appears to be from the redesign of the Sundstrand-drive 10EE to create the inline-exciter era 10EE.
The Rear Spindle Bearing Spacer [Parts Picture E2A-7] is Monarch part EE-1125, shown in dark blue, above. (This same part has been in use from the Sundstrand 10EEs all the way to 1980 and probably beyond.) It's job is to help control the position of the rear spindle bearing on the spindle. Note that it rotates with the spindle; if it's a loose fit, it will cause balance and vibration issues. The clearance between the spacer and the spindle, show on the drawing above, is 0.0002 to 0.0009", so it should be a fairly close clearance fit.
Both ends of a 10EE's spindle employ a form of labyrinth seal to prevent oil from escaping. The rear seal on early round-dial machines consists of three parts:
- Rear Bearing Oil Throw Plate [E2A-5; EE-1116] (aka oil slinger), shown in orange, above.
- Rear Spindle Bearing Oil Deflector Retainer [E2A-3; EE-1031], shown in medium blue, above.
- Rear Spindle Bearing Oil Deflector [E2A-4; EE-1122], shown in purple, above.
The rear retainer, EE-1031, attaches to the headstock casting via 4 cap screws. Note that it does not contact the outer race of the rear spindle bearing. It has a counterbore, facing away from the headstock, to accept the oil deflector, EE-1122. The oil deflector has an L-shaped cross-section an is pressed into the counterbore in the retainer. Together, the deflector and the rear retainer form a U-shaped, annular cavity that encloses the fin on the throw plate. Not shown on the drawing is the drain hole at the bottom of the retainer and the channel that routes oil that collects in the annular cavity into the headstock's main (center) reservoir. Both the deflector and the retainer are stationary and do not contact the spindle. This design apparently did not incorporate a gasket between the retainer and the headstock.
The throw plate, EE-1116, is a tight fit to the spindle, rotates with the spindle and does not contact the deflector or retainer. It's held in position by the rear bearing on one side and the Spindle Lock Gear, [E2A-95; part EE-2302] on the other. The lock gear is, in turn, held in place by the Spindle Sheave or drive pulley (not shown on the diagram), which is also a close fit to the spindle (0.0005" clearance, max).
The way the seal works is that any oil that makes its way between the spindle and the rear retainer enters the annular cavity or moves to the throw plate. As the spindle rotates, oil on the throw plate is spun outward into the annular cavity, where it can make its way to the drain at the bottom.