By Tom Newcity




There is no problem gauging how much oil to put into a screw-in oil cup, but how much oil do you put into an Emerson with a closed oil-bath system.  Not enough oil and you could damage your fan, and too much oil and it's overflowing into the gear case to dilute the grease and leak out all over your furniture.  When I first began restoring Emersons, I asked many experienced fanners, "How much oil goes into an empty Emerson"?  The answers were "a few squirts", "a half dozen or so drops", "not too much", "not too little", etc, etc, etc.  Just seemed like there should be a more accurate method.

If only there was a window to see into that oil chamber.  Well we now have that window.  An Emerson blade hub with the end cut off in the lathe and a medicine bottle cap put us in business. 


Now with the ability to see the oil level in the chamber, the next step was to find a measurable delivery system.  A six milliliter hypodermic syringe with a 1 1/2" blunt tip needle was the answer.  The blunt tip needle is also ideal for injecting the oil deep enough to help reduce the back-flow caused by an airlock in that closed system.  It helps to tilt the motor forward when filling.

After testing with a 26646 motor, 3 milliliters was determined to be a proper amount for that system.  Oil was injected until it began to back up, then run and repeated.  Initially the oil flows through the rotor tube to the hub.  Oil can only get to the rotor reservoir through the small holes in the rotor shaft and that takes a while.  After about one hour of continuous running in this trial, the oil reached a proper level. 

McMaster-Carr has syringes and blunt-tip needles.  I'll have some at Fan Fair also.



Next trial was to determine if oil was coming back into the gear case via the oscillator drive rod.  An Emerson 77646 was sacrificed for this trial.  A hole was placed in the top of the gear case to allow monitoring and the lower half of the gear case was left off during the trials. 

Oil did come back into the gear case via the oscillator drive rod with the motor running following the initial injection.  The amount was negligible, but was found to be less when the oil was injected in smaller doses.  Starting out with 2 ml, running for about 30 minutes, then injecting the final 1 ml worked well.

All of these quantities were determined with the motor in a level position and starting the tests with the inner chamber of the rotor clean and dry, and the rotor shaft and shaft holes clean and dry. 

I'll have this on display at Fan Fair.  If you have any questions before then, just send me a PM.  See you then and good luck.