Recent interest in electric motors installed in reproducing pianos has
brought out an abundance of new information.  However, some of the
information that I have read in these current postings and some found
in the MMD Archives suggested by Robbie is erroneous.  Perhaps I can
add a few comments that might clarify the topic of lubrication.

Motors found in the Duo-Art are usually Holtzer Cabot and contain
lubrication systems based on oil-soaked yarn packing at each end of the
armature shaft.  These motors must be removed from their mounts in
grand pianos to access the oil ports.  I have seen early Duo-Art pianos
with "well and wick" lubricating systems; but I don't recall the motor
brand, and the installations may not have been original.

Ampico pianos often have Holtzer Cabot motors, but Westinghouse motors
can be found, too.  Pianos from early Ampico production, up until about
1923, may have Holtzer Cabot motors that do not have the yarn-packed
oil system.  Rather, these motors have lubricant wells with a spring-
loaded wick.  This style of motor is easy to recognize because it is
cradled in a circular metal ring, which in turn mounts to the piano.

Servicing Ampico motors equipped with the yarn packing and oil,
requires removal from the piano.  Motors with lubricant wells should be
removed too, but in some cases, it is possible to awkwardly add
lubricant while the motor is installed.

Adding fresh lubricant to these motors should be included in a normal
rebuild job.  Original motors found in unrestored pianos containing the
yarn packing usually have some viable oil present even after 80+ years,
and the bearings should be OK.  However, running the motor without
fresh oil will likely destroy the bearings in a short period of time.
By contrast, the well-and-wick style motors probably have bad bearings,
since that system required considerably more attention and frequent
additions of lubricant, because it tends to leak out, and the wicks
don't keep sufficient lubricant on the bearings.

Searching the internet can yield many answers about proper electric
motor lubrication.  I don't have a good recommendation for oil for the
well-and-wick type motors, but the oiled-yarn motors should have a
simple non-detergent oil rated SAE 20 weight.

Electric motor oil has a different task than does automobile engine
oil.  Automobile engine oil is required to do several things.  Yes, it
provides lubrication, but it also must circulate and in doing so, it
provides some cooling to the hottest part of the engine.  Since
combustion is taking place, tiny particles of combustion products are
collected in the oil, which holds them in suspension.  This is where
the detergents in oil come into play by aiding in that suspension
process.  The detergents also contain inhibitors.  In time, the oil
becomes too dirty and must be changed.

If we are lucky, electric motors have no combustion.  The oil does not
really circulate in yarn-packed bearings or return to a reservoir, as
in an automobile.  The oil must provide a film on the bearing so that
there is no metal-to-metal contact.  The film allows the shaft to float
on a few molecules of oil.  If the film breaks down, the floating
stops, and the bearing starts squeaking as metal-to-metal contact
occurs.

Previous statements about not using 3-in-One oil are partially wrong.
The "3-in-One" company makes a high quality motor oil specifically for
electric motor bearings.  Read the container label.  If it says "for
1/4 horsepower motors", it is a perfect lubricant for piano motors.
If the container says "Penetrating Oil" or "Household Oil", it is not
to be used as a motor lubricant.  The labels are explicit.

Good electric motor oil should be slow evaporating, non-detergent, SAE
20.  Clock oil is very slow evaporating, but is not designed to be used
in higher temperature applications such as electric motor bearings.
3-in-One motor oil, and others that are labeled as "long lasting", are
slow evaporating.

Match the lubricant to the application.  Read the label.  SAE 20 is
ideal.  3-in-One motor oil for fractional horsepower electric motors is
ideal.

Bob Taylor
Missouri