Restoration of a 1947 Vintage Singer Model 15-90

This restoration is a Singer Model 15-90… it is the same machine as the 15-91 but with an external motor. I have done several of these machines, both 15-91’s and 15-90’s. In my opinion, aside from the 15-91’s direct gear drive potted motor versus the 15-90’s belt drive external motor, there is no difference in the sewing experience between the two. In construction, features, function, and feel they are the same. Both create a beautiful laser straight stitch.

To start with, this machine is in good condition. The decals are excellent, The machine’s paint finish is good. The shellac is intact on the sewing bed, but this has more of a smooth “matte” finish in the paint compared to the smooth clear finish I dearly love. There is nothing wrong with this. I attribute this to use and I suspect that this machine was used often. On first inspection, I noticed that the finish on the pillar of the machine had been dulled from improper cleaning. portions of the shellac coating is worn off of the sewing arm and the pillar. The decals are still protected by shellac and that accounts for their condition. The challenge in this restoration is cosmetic reconditioning, and it will rake a lot of work to get the best it can be. In any event, I expect that the finish can be brought out to a very good condition. The rest of the machine will be completely disassembled and the machine will have a detailed restoration. This post will be a little different, and I hope you bare with me because I lost many of the pictures I took when working on this machine. Normally I take a bunch of pictures and I sort thru the pictures to show as best I can what is going on in the restoration. Please bear with me on this project, I am using some pictures I would normally discard (blurry, dark, angle, etc.). All of the steps are shown, but not as clearly as I would like for you to see. I may also use the same photo to show different steps taken on the same area because these steps are performed at different stages of the restoration. Still, there are enough to get thru! That said, here is the machine before restoration…

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Now the machine is completely disassembled… everything is removed from the body of the machine, All of the removed parts are either hand cleaned or ultrasonically cleaned. All of the parts and pieces laid out below have been ultrasonically cleaned and ready to be wire brushed.

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The parts are restored to like new condition by wire brushing…

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The top arm shaft, the hook shaft, the needle bar, and the presser foot bar are polished to be glass smooth…

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The bushing bores where the shafts rotate or move up and down are brushed and cleaned… When reassembled together, these will move smoothly.

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There are parts that are removed that have cover plates on them. It is important that these covers are removed for cleaning…

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Now my attention is turned to the body of the machine. The plan here is to deep clean as usual, but to use glaze polish to level the shellac and remove any oxidation in the finish. The goal is to get a deep rich finish. Glaze polishing is not very aggressive, and progress is slow so it done over multiple sessions. The first few sessions are done with TR3. TR3 is a glaze polish that is slightly more aggressive than the final polish I use. Although it is a fine grade polish, I use it for the first polishing because I like it’s slightly rougher cut to smooth out imperfections faster. The final few polishing sessions are done with a product called Meguiar’s Mirror Glaze to finish it off.

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The result is a much “blacker” finish, and it is getting pretty smooth. This will be repeated until it is a good as it can be. But, now is a good time to repair any chips, since subsequent polishing will also smooth out any repaired areas. The chips are pretty small and I debated doing it at all, but with this much time in a restoration it seems appropriate. There is plenty of time to work. The painted areas will need to cure for at least 24 hours before a second reapplication, and 2-3 days before it is leveled and polished.

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Note that the paint matching will not remove a chip, but it will make it blend into the machine and be far less noticeable. This is shown in the next series of photos.

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There are a few small defects in the decals, and I decided it would be good to try and fix these areas… more because I am trying to stretch my boundries in my restorations and improve my skills more than it is anything else. Fixing decals is something I shy away from, but on this machine, the defects were so small and so few, I decided to give it my attention.

Singer developed dozens of decal sets over the years to adorn their machines, Generally they are ornate and finely detailed, and the older the machine, the more ornate the decals were! You will find machines with decals that are multicolored, gold, and even combinations of both. It would seem that the decals on this machine are not to hard to fix because the decals are gold. But, now I need ask myself, which color of gold is it? Singer decals, like the machines they adorn, mellow with age. Some machine have bright gold decals, some have a mellow gold tone, and some have decals with gold shaded “highlights” that are a combination of the two. Each machine is unique and different in the way the decals present themselves. This makes color matching difficult. The first thing I need to do is to try and match the decals to different shades of gold to get best color of I can and go from there. To compare colors. I use a piece of scotch tape to act as a pallette… the “U” is where I tried mixing the colors. If you look at the bottom right of the pictures, you will notice a “bright” spot on the decal. This is an area I repaired using the far left color it is the closer match.

Proceeding with this color, I am correcting all of the areas I see.

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Keep in mind, the decal lines are very thin. Using a fine tip artist brush with the bristles trimmed even finer, the repair is done using a 20X jewelers loupe… For the light shroud, I used a 40x gemologist microscope. But… my hands are only so steady, and the margins of the decals are not precise… yet. Everything is trimmed to the margins of the decals. A coat of shellac is applied over the repairs to seal them. These areas will be left for now, and the restoration moves to the motor.

The motor on this machine is a 0.5 amp vintage Singer motor. For a straight stitch machine, despite manufacturers offering more and more powerful motors, this motor is quite adequate for this machine. The wires are cracked and need to be replaced, the armature shafts will be polished, the commutator will be polished, and the brushes will be conditioned if needed. Because this motor uses grease wicks instead of oil, the grease wicks will be replaced. After performing these steps, there is nothing else that can be done to restore these motors, and if it doesn’t run, it never will, and if it does, it will run great!

The next few pictures show these steps with captions…

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After replacing the wires, the motor is reassembled and bench tested. Fortunately, the motor runs great!

Now comes the restoration of the light fixture. The wires are cracked and need to be replaced… now, this type of light fixture uses metal rings that snap and hold the shroud together. In addition, to replace the wiring, I need to cut the new wire to the exact length of the old wire, de-solder the contacts from the old wire, and solder them to the new wire… I hate disassembling these light fixtures because the circle clips are a pain to remove. I would advise avoiding it if at all possible. Here it can’t be avoided, so enough whining about it. Here are pictures of the light restoration with captions…

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After reassembly, the light fixture is set aside and the next step is the top tension assembly… It is disassembled and cleaned… The take up spring was bent so it was replaced.

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Next is the bobbin winder assembly. The main bobbin winder spring was broken and it is replaced.

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Because the cosmetic restoration will take a few more days to complete, there is plenty of time to put the machine together, make the proper adjustments, and figure what else I can do to this machine… The first thing to do is attach the light and motor. The plug terminal needs to be wired with the new wires from the light and the motor. These in turn need to be cut to length and have terminals soldered to the ends. Shrink tubing is used to insulate the terminals.

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The front cover, the rear cover, and the balance wheel knob is polished…

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Can’t see the difference clearly in photos, but the micro scratches are polished out.

The machine is assembled, adjusted, and run. The last bit of details to complete the restoration is another application of glaze polish, and for this machine, a coat of carnauba wax.

Now, The machine is finished. The mechanical restoration was from the ground up, so there isn’t much to say except the machine sews and feel like it must have felt 72 years ago. It is silky smooth, quiet, powerful, and has a fantastic stitch.

As I said in the beginning, the biggest part of the restoration was to get the machine looking as great as possible. The decals were in great condition, but the paint needed a lot of work to restore the best original finish possible. For this machine, this meant multiple applications of different grades of glaze polish. The cosmetic restoration took days to complete… more than any other. The results however show me that it was worth the work. The japanned finish on the bed looks great. The mottled and dull finish on the sewing are and pillar look really good as well, keeping in mind the desire to preserve the original finish and character of the machine. The following pictures show what I mean.

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I often talk about expectations when looking at what to expect from a restoration. In this case, I thought I would end up with a “3 foot” machine… That is, any defects would be indescernable from 3 feet away. What I ended up with is a great “2 foot” machine, or if your eyesight is like mine, a good “1 foot” machine. The only way to show a comparison is before and after.

Before Restoration…

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After Restoration…

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And then there is the stitch…

So there you have it… The restoration is complete and I could not be happier with the results.

If you like what you see please visit our Etsy store at https://www.etsy.com/shop/pungoliving, and see this Singer Model 15-90 and all of our other restored fine quality vintage sewing machines. If you have any questions, please contact Lee at Pungoliving@gmail.com.

Thanks for reading and tell me what you think!