This article shall focus on the historical nature and inherent properties of fan lubricants that were used by the original manufacturers as well as subsequent lubricants as technology improved. I have also included a section on lubrication methods on several fan types featuring Royal Purple Synthetic Lubricants favored by fan collectors for it's many fine qualities. This section lightly covers other topics such as end float adjustments and specific lubrication suggestions on a few particular fans. This article is a general source of fan lubrication knowledge and does not address many specific fan lubrication situations. If anyone has a specific question not addressed in this article, the Forum is the place to ask as the answer may well serve a fellow AFCA member.
The lubricants originally used in antique fans and other machinery are composed of rendered animal fats otherwise known as triglycerides. These lubricants are made by boiling raw animal flesh until the pure fat separates. The molecular structure of these early lubricants resembles strings of spaghetti tied together at one end. Electric fan motors operate at high speeds and generate heat in normal operation. Rendered lubricants would naturally attract oxygen free radicals leading to rapid oxidation and breakdown under heat and load conditions. Many electric fans suffer from worn bearings, gears and shafts due to the poor lubricating characteristics of the early lubricants as well as owner neglect.
Refined oils were a great improvement over rendered animal fats although the tendency for refined oils to form grease deposits under heat and oxygen exposure did not improve much. The molecular structure of refined oils resemble long stands of spaghetti. As the rotating parts of a fan move, these strands become increasingly tangled as the lubricant molecules are in rapid random motion thus producing heat. The increasing heat causes faster breakdown of the lubricant and premature wear on the components.
Refined oils have poor viscosity consistency. The motion of the gears or other parts "stirs" the lubricants and thins the viscosity. This phenomena is known as Non - Newtonian Rheology. An attempted solution for poor viscosity used to be to simply use a heavier lubricant. However, this would create additional work for the motor, increasing drag and wear at startup. These are certainly undesired effects in an old fan. Refined lubricants are plentiful, cheap and a far better choice than rendered lubricants.
Synthetic lubricants, such as RP are the best choice for fans or other fine machinery. Synthetics are artificially constructed so they do not oxidize readily. The molecular structure resembles small spheres and are designed not to tangle. Less heat is generated resulting in slower oxidation and breakdown. High grade 100 % synthetic lubricants like Royal Purple operate well in continuous high heat situations and have a greater shear strength. This is an important consideration when a fan has expensive to reproduce gears. Synthetic lubricants have properties that are designed to transfer heat faster and enhance molecular bonding to the surfaces of parts and thus lessen initial start up wear. Start up is when most wear occurs between moving parts.
Early desk fans use oil cups located under the front and sometimes rear bearing housings. These cups serve as oil reservoirs. They work in conjunction with a spring loaded wool wick to transfer the oil to the bearings. On most fans there will be one or two drain holes in the oil galley (area just under the front and rear of a bearing) which serves as a sump to allow gathered oil that has passed through the bearing to pass back to the cup. Heat, age, oxygen and the inherent chemical makeup of the original animal fat or refined oils combined to transform the lubricants originally installed into useless grease. Hardened grease is thus commonly found in the cups upon initial examination. Inexperienced collectors often mistakenly replace old grease found in the cups with new grease. This grease residue provides little protection and blocks the drain holes causing fans to leak when running. Over time, old wicking packs up with hardened grease and dirt and ceases to transfer oil to the bearings. Always replace the old wicking with fresh wool wicking and clean out all residue from the drain holes and oil galleys. Attempting to save an old dead wick is a waste of time, sort of like cleaning an oil filter. The old wicking is impregnated with residue and works poorly at best. Always lubricate bearings with (preferably) a little Thicker RP oil which serves as an assembly lubricant or regular RP if Thicker Oil is not handy.
Take the attached fan blade and pull the blade in and out to find out what adjustment may be required to the rotor. Some fans have a sloppy or jerky motion caused by excessive play due to worn or missing end float shims. This play can be corrected by adding shims to adjust the end float or adjusted play. There should be some play or movement but not excessively so. This takes some practice but is a skill every fan collector should learn as shimming a fan will improve the smoothness of a fan considerably. Unscrew the front motor plate hold down screws and look for an indentation on the bottom of the plate that can be used to separate the motor housing. However, many times there is no indentation provided. If not, rap the motor housing close to the seam with a wooden handle to shake the parts loose. Avoid using a screwdriver tip to pry initially as this could easily mar the paint. After removing the front plate, pull the rotor or armature out. Note that on some oscillator fans such as a Jandus C Frame, this is not possible without further disassembly. There will be a drain hole located in the rear oil galley in most stationary fans. If the stator winding is not to be removed, carefully clean the galley with a rag soaked with varsol. Avoid spilling on the windings or laminated plates. A spill will result in a smelly operation as the windings heat up. Proceed to clean out all vestiges of grease and dirt. Carefully use compressed air to clean the windings of debris. Beware that intense air pressure could damage the insulation or wrapping. This may also be a time to consider soaking the windings with a good quality insulating spray. Prelube the bearings with a little RP Thicker Oil before installing the rotor.
Should the fan be an oscillator, check to see if the gearbox is removable or integral with the back plate. If integral, soak the assembly in varsol to clean it. If removable, carefully remove the gearbox and clean all the old grease out. Remember to never force something that will not move without careful study. The penalty could be a broken part that survived 80 years or more until YOU broke it. ( Been there myself.) There is usually a reason a part will not come off such as rust adhesion or a screw or pin that was overlooked. Soaking with a good quality penetrant is always a good idea on a stubborn assembly. Gentle heat and sharp rapping with a wooden or plastic hammer helps from time to time as well. If there is still a question about removal of a particular gearbox, our AFCA website can provide specific answers from our many knowledgeable members.
Be careful not to lose or mix up the fiber endplay washers located on the front and rear of the armature/rotor. Compressed air works well to clean the vestiges of grease out of the gear teeth and out from under the large "bull" gear. Before repacking the cleaned gearbox, check for excessive gear play. The fiber washers used to set up the gear lash can and will disintegrate over time and the gears themselves usually have developed wear. Sometimes wear can be compensated by adding shims to take up the slack. After the gearbox is shimmed correctly, repack with Royal Purple synthetic grease. Cover the gears and push the grease deep into the gearbox. Do not over pack by filling the gearbox cover to the brim. After the fan is run in, check to see that the grease has settled in.
Examine the spring loaded wick. Make note of the length of wick protruding above the spring. A bent wick means the wick was to long. Take a razor blade and slice the old wick up like a loaf of bread to remove it from the spring. Take a new piece of wool wicking and roll the wick into the spring. Be sure to pinch the new wick with the top end of the spring to hold the wick in place after final adjustment. Before installing the rotor, recheck the new spring loaded wicks length by placing it in the oil cup and installing the unfilled cup on the fan. Look into the bearing and make sure the wick protrudes through the hole a little. Fill the oil cup 3/4's full of Royal Purple regular oil. Allow the wick to absorb the oil and recheck the cup level before reinstalling the cup. If the rotor is not to be removed, look into the wick hole and measure the length of the hole. Cut the new wick accordingly and insert. Screw on the cup and then remove the wick to make sure it is not bent or curled up. Sometimes a lubricating cup will be located on top of the bearing housing such as certain Peerless fans with front gearboxes, early G.E. Pancakes and early Diehls. These usually require no wicking and use grease to service the cup. Use Royal Purple Synthetic Grease mixed with a few drops of RP thick oil for top cups. Lubricate all the linkages and pivots with RP grease.
Be aware that many fans have bearings without a hole for the wick to pass through to touch the rotor shaft. The wick transfers the lubricant to the outside of the bearing and the oil soaks in. These fans use an Oilite type of lubricant soaked porous brass material for the bearings. There are several ways to lubricate these sleeve bearings. The ideal way would be to remove the bearing and soak it 24 hours in RP oil. However on many fans by Century or Westinghouse with potmetal construction removal is not possible or could destroy the bearing housing. If the fan is not to be disassembled, remove the oil cup. Spray a degreaser into the oil cup hole to clean the old residue out. Insert a toothpick into the oil drain hole to block it. Turn the fan upside-down in a place it can stay a while. Pour a little RP oil into the oil hole and let it soak in for a week or so. This process takes time because the bearing is impregnated with old lubricant. Heating the oil will speed up the soak time. After sufficient soaking, clean the oil drain hole. Turn the fan on it's back with the rotor facing up and place some RP oil on the rotor shaft and allow to penetrate the bearing. This will not take long unless the bearing is unusually tight. The rear bearing may be serviced by an access hole
Silver Swans and Emerson Internal Oiler Fans.
These motors use a packing in the oil reservoir. or often is inaccessible without disassembly. There will be a flat head drain plug under the front and rear motor housing. Open it and remove the packing. Take a piece of 1/4 inch wicking and make the length enough for the screw to just mash against the wick so there is a little pressure against the rotor. Otherwise shred the wicking and stuff into the hole until full. Pour enough RP oil to fully soak the wicking and replace the plug. Allow to rest in a upside-down position to soak the bearing.
These fans require lubrication on several areas. The track or groove in the C-frame should be lubricated with RP Grease. Clean out the old hardened grease with a screwdriver and varsol dipped rag. Squirt some RP Grease into the track. Turn the fan on and it will push out any extra grease. Open the gearbox by removing the four screws securing the cover. Make note of the exact location of the parts inside. Inside will be a very difficult to make gear and another part the name of which escapes me. Clean the old grease out with a toothbrush and varsol. Wipe or blow clean the inside of the cover as well. Push RP Grease into the gearbox making sure the gear teeth are covered. Do not use too much grease or it will ooze out when the cover is replaced. Next are the oil cups which are the same as other fans. Do not forget to place a little RP Grease on the motor pivots as well.
These gearboxes are like differentials. They use a horizontal main gear and a pinion. Use RP Thicker oil in these models and not RP grease.
For the Westinghouse Gyro, the bottom bearing should be packed with RP Grease. Be careful not to over pack or there will be leakage onto the commutator rings. The small gear that runs the steel drive belt should also be packed with RP Grease.
These inclined fans tend to drip out the front bearings due to wear and inclination. I have experimented with about a 50/50 mix of RP oil and RP Thicker oil that seems to work best but have not solved this problem entirely. Some fans require varying mixes depending on bearing wear.
For the Rotaire fans, the delicate gears and swivel joint should be packed with RP grease.
These fans have a brass oilite bushing riveted or screwed into the motor housing. Inside the bearing housing will be the bearing with the remnants of a wicking that was wrapped around the bearing . I have found many of these wicks are nothing but dust. On these fans make a new wick with a small piece flat felt Drop the bearing into a jar of RP oil and allow to soak if to be reused. These bearings are usually worn however and should be replaced.
These fans were rarely lubricated with any regularity. As result many fans suffer from shaft and bearing race wear causing noise and wobble problems. Typical ceiling fans like Emerson's use oil immersed ball bearings mounted a race. On some early models, like Turek friction drive fans, a single ball bearing packed with grease was used to suspend the vertical rotor. Some primitive fans like belt drive fans and very early electric models used grease packed babbit bearings. Manufactures like Guthe and one particular model by G.E. use a sideways mounted grease cup and an oil reservoir using bulk wool packing to hold the oil.
On electric ceiling fans using oil immersed bearings, remove the oil cup by unscrewing it. Clean out the old grease and dirt and replace the felt to be found under the bottom bearing race. On some models there are spiral oil grooves cut into the shaft. Clean these grooves carefully. Use compressed air to clean the parts. If the bearings are damaged or worn, replace them. Carefully Inspect the rotor shaft for wear. These usually could benefit from replacement or repair. To lessen bearing noise, place a piece of rubber under the bottom bearing race. Use a mix of RP regular oil with a little RP thicker oil to just cover the bearing. Over filling will certainly cause leaks. Use Teflon tape to seal the shaft threads that are used to attach the oil cup to the fan. Fans using a single ball bearing should use RP grease with RP Thick oil for lubrication.
Scotty MacClymonds email@example.com