I have recently seen multiple forum posts on lubricating Singer vintage external motors. To most folks, the obvious sign that a Singer motor is lubricated with grease is the presence of small tubes at the end of each end of the motor. While many Singer motors were fitted with tubes and wicks for filling with grease, some were fitted with tubes and wicks that were lubricated with oil. While they look very similar, they are in fact very different. Here are some pictures to show what I mean.
This motor was fitted to a Singer Model 66. If you look closely, at each end is a raised tube. This tube contains a grease wick.
Here is another example of a motor on a Singer Featherweight…
If you look closely on the front of the motor, you will see a small tube at the 9 o’clock position looking at the pulley. This tube also holds a grease wick. There is also a grease tube at the back of the motor.
The next picture is a motor fitted to a Singer model 15-75.
Looking at each end, we see what appears to be grease tubes. In fact, they are not grease tubes, but oil tubes. These tubes also contain a wick, but it is an oil wick, not a grease wick.
Though they look similar, they are very different. Proper lubrication of this motor requires oil. A motor designed for grease lubrication requires a grease formulated to melt at a certain temperature. Proper lubrication of these motors is vitally important, and the life of your motor depends on it.
You see, a motor designed with grease wicks should not be lubricated with oil. The oil will seep into the motor and contaminate the copper windings. Over time, this will cause the motor to run slow, or not at all. On the other hand, if the motor is designed for lubrication with oil and grease is substituted, the grease may not flow freely to the shaft and bushing where it is needed and starve the motor of lubrication. Again, the motor will overheat and damage to the motor will occur.
How do you tell which is which? Well, it is not readily apparent and it requires close examination. Both use a round felt wick in a tube, and they look very much the same. It is no wonder why people trying to do the right thing and lubricate their motor, unwittingly end up doing something detrimental instead. I will try to explain how to tell the difference so you can properly lubricate your Singer motor… with grease, or with oil as the motor requires
Lets start with the motors that have grease tubes. The grease tube provides a reservoir for a small supply of grease that is in contact with the grease wick. This is accomplished by using a spring in the tube that pushes down on one end of the grease wick. The other end of the wick is in direct contact with the motor shaft. The grease is formulated to melt at approx 115 degrees F. and this temperature is achieved in normal operation of the motor. As the motor melts the grease, it turns into a liquid and is transported thru the wick to the motor shaft. This liquified grease lubricates the shaft and the bushing it rotates in.
One way to determine if it is a grease wick and not an oil wick, is to probe the opening in the tube with a pin or a needle. There should be little or no resistance to the probe as it passes thru the spring, until it hits the grease wick… maybe a 3/16ths to a 1/4 of an inch deep or so. This space is the grease reservoir. Here is a picture showing a grease wick…Notice the springs that form a reservoir for the grease, and it also keeps the wick in contact with the shaft. Bottom line, if there is a reservoir space, the motor requires grease.
Now, lets look at an oil wick…
They look very much the same, but notice that there is no spring, or space for a reservoir. The wicks are saturated with oil. If you probe the tube with a toothpick or a needle, there is no gap. The wick extends to the top of the tube. If there is no gap, there is no reservoir, and the motor requires oil.
Unfortunately, they only sure way to tell is by dissembling the motor. As I said previously, if it is a grease wick, when the shaft is removed from the motor case, the felt will pop down thru the bushing and be observable.
You can see the wick and the end is curved where it formed to the curvature of the shaft.
A motor with oil wicks is completely different. It uses a self centering bronze bushing shaped as a ball. A slot is cut into it, and the oil wick rests in the slot. It never touches the shaft. The bronze ball seats on a felt washer, and is held in place with a metal cup that seats in the motor case. The oil saturates the felt and lubricates the shaft. Here is what these components look like.
As you can see, this is very different from a motor that uses a grease wick.
The difference between a grease wick motor and an oil wick motor is not easy to discern by looking at them. I wanted to reach out and explain, and hopefully describe how to tell difference. It is important to know so people can perform the proper maintenance these motors need and the use the proper lubricant… grease or oil to maintain them.
I have read on more than one forum, where people wanting to do the right thing, discovered that they could not force grease into the tubes because the felts came to the top of the tube. Too often, the advice was to remove the felt to make room for grease… when in fact it was an oil wick.
I hope this information is useful to you and hopefully it will help you maintain your motor to ensure years of trouble free service.
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