Other parts of this series:
The machine above is a Singer 15-30 manufactured on January 6, 1920. At some point in its nearly 100-year life, the machine was "electrified" with a motor and a light. Throughout this series, we'll re-beautify the machine and convert it to a hand crank.
I'm going to show you how I break this machine down for general reconditioning - something a lot of collectors call a "spa day." The plan is for this tutorial to be very accessible to a beginner. We're not going to remove any components that might leave a "newbie" struggling to reassemble them. In fact, the bobbin winder will be the most challenging part.
The older Singer 15 models have fewer features than later model 15s, so while your 15 might have a more elaborate stitch regulator, dropping feed dogs, or reverse, we're nonetheless going to cover principles and techniques that will help you when working on the more common 15-90 or 15-91.
Get Acquainted with Part Names
This diagram will help you become familiar with parts and general areas of the machine.
When choosing a screwdriver, use one that fits the screw head slot snugly while seating itself flush to the bottom of the slot. If too loose, you may strip the slot of the screw, widening the slot so that a screwdriver tip will not fit it properly. Likewise, if the screwdriver tip is too large without fitting flush to the bottom of the slot, it can slip loose and also damage the screw head. The Vintage Singer Sewing Machine Blog has an excellent guide for choosing the correct screw driver tip, but if you cannot match the quality of the hollow-ground tips shown in the guide, simply choose the best-fitting household screwdriver you have for each screw you remove. If a screw is stuck, you must use penetrating fluid such as Bluecreeper and heat to avoid stripping the screw. More on this throughout the tutorial.
Photographing and Grouping Your Parts
If you are not 100% certain that you will remember what a part or area of your machine should look like after reassembly, take abundant photos. If you're new to this, you will be very thankful for grouping your parts in small plastic containers or sandwich bags. You can use masking tape to "tag" even small screws and parts.
Our essential steps here will be similar to working on an electric 15-90, which also has an external motor. If you are fortunate enough to own a 15-91 with a potted motor, you have a very different (and desirable) direct-drive motor. If you wish to delve into your potted motor you will want to read this series of posts at The Vintage Singer Sewing Machine Blog. Sadly, that blog hasn't been active since 2013, but the existing information is excellent.
Make certain your machine is unplugged for disassembly. I know it sounds like common sense, but please take great care with electricity.
The wiring on my 15-30 has already been cut away from the motor. We must remove a single bolt or heavy screw (depending on your machine) where the motor bracket attaches to the motor "boss" mount. The belt is then easily slipped off the balance wheel with the motor removed. In the case of this particular 15-30, I will not use the removed motor for reassembly since I intend to complete the machine as a hand crank.
If maintaining your machine as an electric model, inspect your motor for frayed or cracked wiring. Please don't give it just a quick once-over. Inspect every inch of the electrical cords! If your motor is good or salvageable, set it aside in a safe place for now.
On our 15-30, we need to also remove the electric light. The black cover plate shown below - behind my finger - serves as a bracket for the light as well as a cover plate. Notice the cracked wiring on the light as well. The light will not be used on reassembly for a hand crank machine.
Your 15 may have an original Singer light that is wired directly to the motor and attached to the machine differently than mine, but it will still be easy to remove. Remove the thumb screw to remove the cover plate as well as any screw holding the light assembly into place.
If the thumb screw is seized and too tight for your fingers, use a thick piece of leather or comparable material to protect the thumb screw as you loosen it with pliers. The padding ensures that you don't unnecessarily blemish the grooved area. It sounds minor, but when the thumbscrew is polished later, it will look nicer without signs of pliers having marred the surface. Small details will lend themselves to an overall more beautiful machine when complete.
With the cover plate removed from the back of the upright pillar, we can see the internal mechanism.
The Balance Wheel (Hand Wheel)
Fortunately my 15-30 already moves freely when I turn the balance wheel. However, if a machine is seized and the wheel does not turn easily, I recommend that you lubricate and heat the rotating cams, linkages, and moving areas of the machine until the balance wheel moves freely, causing the needle bar to move up and down normally.
Liberal use of a high-grade penetrating fluid such as Bluecreeper, combined with heat and patience will loosen most parts. A hair dryer can generate adequate heat, but a heat gun or carefully used butane torch may work faster. Keep in mind that heated metal becomes, well, hot. Allow metal to cool to avoid burns.
With a free-moving machine, you can remove the balance wheel knowing that you'll easily continue your work. Remove the set screw on the stop motion wheel. It is the shiny (or perhaps rusty) knob with the grooved edge intended to provide a good grip when properly loosened by hand.
With the screw removed, you can typically loosen and remove the shiny (or rusty) stop motion wheel by either holding the balance wheel in place with your other hand, or the needle bar, as you loosen the stop motion wheel.
Beneath the wheel you will find a tabbed stop motion lock washer.
With the tabbed washer removed, your balance wheel should slide off. If it feels stuck, try a firm pull. If necessary, apply penetrating fluid and heat. Take great caution if you attempt to tap the wheel off the shaft, because the shaft can break from overzealous tapping which will actually apply abrupt pressure against the shaft. I've seen cracked shafts. I recommend that you patiently work with penetrating fluid and heat to remove a stuck balance wheel.
The Balance Wheel Cover
There is a single screw holding the balance wheel cover in place. On many Singer models, the bobbin winder is attached to the cover as seen below. You may find that you prefer to first remove the bobbin winder from the cover, depending on the position and angle of the screws. With my 15-30, I chose to remove the cover first.
The Bobbin Winder Assembly
The bobbin winder is comprised of many small parts, including springs. For a beginner, it will likely be the most challenging part to reassemble later. I want you to believe that you can manage to do it successfully, because once you have conquered one, you will have much greater confidence with your mechanical ability. The machines you work on in the future will be less intimidating.
Take many photos of your bobbin winder assembly from multiple angles before and after it is removed from the machine.
If you're absolutely terrified by this mechanism, you could certainly clean it without further disassembly. It will be difficult to polish all the shiny metal effectively, and it is a less than thorough job unless your machine's bobbin winder is already in great shape.
Having detached the bobbin winder from the balance wheel cover, I photograph and take notice of every detail, like the position of the tip of the spring below.
As you remove springs, inspect them for broken tabs. Without the tabs, the spring won't work correctly.
Work patiently on your bobbin winder, taking great care to continue photographing it at each step of disassembly. Below I've taken notice of the thin washer's position. Upon reassembly, without an understanding of how washers integrate with an assembly properly, you might have difficulty. Photos, photos, photos!
Another spring is revealed:
We're seeing just how dirty and corroded this bobbin winder is between all of it's moving parts. So sure, we could have liberally injected penetrant or sewing machine oil into the assembly repeatedly to improve its condition, but for an assembly as neglected as mine, I want to know that it is thoroughly clean.
The bobbin tire was so hardened that I had to break it off with pliers. If you find yourself doing the same, just be careful not to press your pliers against the bobbin tire pulley.
On the section of the bobbin winder shown below, I'm choosing to not remove the screw for disassembly. I can see that I'll be able to clean and polish this section easily, and I'm comfortable leaving it intact.
With the bobbin winder disassembled, be sure to keep the parts grouped together so that you don't have to figure out which screws it requires later.
Thread Tension Assembly
A dirty or neglected machine can almost always benefit from a thorough disassembly and cleaning of the thread tension assembly. Mine is looking pretty rough below.
I've decided to remove the face plate before removing the tensioner. I remove the two screws that hold the assembly in place and allow adjustment.
Pay attention to the order of the parts as they are disassembled. The tension regulating thumb nut:
The tension spring removed:
The tension release disc and two tension discs removed:
The tension release pin removed:
The inner barrel is stuck within the outer barrel, and here I'm using Bluecreeper penetrating fluid to begin loosening the seized parts:
The Bluecreeper was enough. I didn't require heat. My fully disassembled tensioner:
This 15-30 tension assembly is much like what you will find on Singer model 66s and 99s.
The Newer Model 15 Tension Assembly
These diagrams will help you to disassemble and reassemble the tensioner on a more modern model 15-90 or 15-91:
Also, we have an article here that might be helpful:
The Needle & Shuttle Areas
Remove the hook slide cover plate by rotating it a bit so that the underside clips will release.
If you find that your throat plate screws are stuck, use your penetrant and heat.
A long screwdriver with an appropriate tip can often provide better leverage than a short screwdriver for challenging screws.
Sometimes a ratcheting wrench with a screwdriver bit can provide the required leverage for a stubborn screw. Remember: patient use of penetrant and heat will accomplish more than fighting the screw with the screwdriver.
Remove the thumb screw that will allow the presser foot to be detached:
Remove the thread guide and needle clamp:
Remove the feed dogs:
Remove the shuttle race body by removing the two large screws:
Remove the screw that holds the shuttle hook retainer in place:
Remove the shuttle race cap. This is definitely optional if you find yourself struggling with the small screws, but I prefer to remove it for cleaning. As always - penetrant, heat, and the proper sized screwdriver!
Presser Bar & Face Area
If you've accomplished the preceding steps, the area beneath the face plate shouldn't intimidate you at all. We have two screws to remove here: 1) the screw holding the presser bar lifter in place; 2) the screw that holds the presser bar guide in place. See below:
The presser bar lifter will likely be easy to remove. Encourage it with penetrant and heat if necessary.
Meanwhile, my pressure regulator thumb screw wouldn't turn by hand, and my presser bar was frozen to the guide. I applied Bluecreeper and heat:
I used the leather and pliers to remove the pressure regulator thumb screw:
My presser bar was really stuck. I carefully tapped it downward to jar it past the stuck point. I left the pressure regulator thumb screw extended but still mounted to serve as a "channel" for my tapping punch to travel downward.
Driving the presser bar downward ultimately releases it from the presser bar guide:
I must also point out that beneath the pressure regulator thumb screw, you will find a washer. Once the pressure regulator is removed, you can also easily lift out the long spring.
I'm left with an area beneath the face plate that will be easy to clean, but without disassembling the mechanism that drives the needle bar. In the next part of this series, we'll easily clean the needle bar in place. This is appropriate for a beginner.
Due to the stark nature of the mechanisms beneath the bed of the Singer 15, a beginner should not feel that they have to disassemble this area. We can clean the rocking shafts and linkages easily in the next part of this series.
If you accomplish the steps above, you will be left with about 70 separate parts. My photo looks a bit intimidating to the inexperienced - but your parts are all grouped and labeled, right?
Part 2: Cleaning and Polishing is now available!
Have a look at Still Stitching
It's the only feature-length documentary on vintage sewing machines. You can purchase it here.
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