Saturday, April 7, 2012

Reader Questions: Rewiring a 99?

All photos in this entry by Azul from California

Azul from California writes,

I was excited to discover your motor rewiring series, but I have a model 99, which does not have the potted motor and does involve a light switch. The motor is mounted on the side, as seen below.

What I have is a Singer 99-13 (according to the Sandman Singer identifying page) from 1937 which I picked up off the street. It’s in excellent cosmetic shape, but the wiring is in bad shape and down to bare metal in parts (mostly due to my boyfriend pulling away the corroded/melted bits).

I do know how to solder, and have access to the necessary tools and materials (although not yet, alas, the Chapman screwdrivers). My boyfriend knows how to repair electrical stuff in general, but does not have Singer-specific knowledge, although he’s enthusiastic and unworried about this (“it’s a light” and “it’s a motor,” he says). I did take the machine to a local repair place, where they seemed to think the wiring problem not too bad, they doubted that there was internal damage inside the motor, but of course would have to take it apart to know for certain.

My question is this: Do you think your tutorial, along with general principles of electrical repair, would be sufficient to work on this motor, although it’s not exactly the same type as the one in your tutorial? Or are there Singer specific issues that would make you recommend instead taking it to a professional, to for example avoid electrocution :o), or messing up the machine further? I’m not sure if you’re able to answer that, but thought I’d ask.

First off, congratulations on the free 99! That's an awesome find.

Secondly, good on your boyfriend for pulling off the rotted wiring insulation. I’ve seen sellers completely ignore that, as if hoping it will go away. As you can see, the wiring can easily come into contact with the body of the machine, which is all metal. That’s bad news if left untended.

To answer your question: While electricity is obviously dangerous if not handled properly, there is no Singer-specific issue I can think of that would prevent someone with knowledge of “general principles of electrical repair” from correctly re-wiring your motor.

Because we live in a country where people love to sue each other, I think I cannot just tell you to go ahead and do it. But the "sideboard-mounted" motor on your 99 (I put that in quotes because “sideboard-mounted” is not an official term, it’s just what I call it) is a simple and basic universal motor, the same you'd find on a 66, a 206, a 15-90, or a 201-3. The Featherweight 221 would also have a similar motor, with slightly less power. Bottom line: The principles of re-wiring yours would be the same as in the potted motor tutorial, and at the very least you would not have to deal with the worm removal shown in the potted motor tutorial (though you would still have to deal with brushes, grease wicks, the washer on the armature shaft, et cetera). Your motor simply turns the pulley sticking out of it, which in turn drives the belt, simplifying things a bit.

As long as you competently re-wire the machine in the exact same configuration in which it originally was, and using the proper materials, I would think you'd have no problem; but of course I do not have first-hand knowledge of you and your boyfriend's exact skill levels.

Also be aware that if worse comes to worst, you can buy simple replacement motors and install those on your machine, should you not feel like tackling the job. The reason I wrote the tutorial specifically for the potted motors is because those cannot be replaced with new motors due to their unusual design (i.e. the way that they fit onto the machine).

If you do decide to buy a new motor, I recommend Sew-Classic sewing machine supplies. While I've never bought a replacement motor from them (I always re-wire mine myself, to save money and because I find it satisfying), I've bought many other parts from Sew-Classic. Jenny, the woman who runs the company, is knowledgeable, responsive via e-mail in case you don't know exactly what you need, and has a (well-deserved) great reputation. She’s my go-to person when I need parts.

If you do decide to tackle it yourself, remember to take lots of photos as you disassemble the motor, so you have a reference for re-assembly. And a replacement motor is less than $25, which should take some of the pressure off.

Good luck with it,

- Rain


  1. Thanks for this post (and thanks to Azul for asking the question). I've been wondering about this. I have a Featherweight with some problems (I think, the foot pedal certainly doesn't work as it should) and might try tackling them myself some day.
    I also have an Elna Grasshopper with motor problems. A bit different probably, but your blog really makes me want to try and work it out. Right now I don't have the time, but I'm really looking forward to when I do.

  2. What a beautiful Singer 99. I love them!!!

    I, too, have had great experience with Jenny at Sew-Classic. I did buy a motor from her after I totally botched one up just inspecting the brushes. I was happy that I did because the motor is fast and quiet. I think it probably is better than the old one I messed up. So it all ended well.

    The light is no problem to re-wire and you can't buy those new. Have a great time.


  3. Beautiful machine, and what luck to find it streetside :)
    Enjoy ~

  4. awwww, i NEVER find cool machines on the street. (sound o foot stamping) ahem. I second that it's not particularly difficult to rewire an external mount motor. But I'm not advising you to do so, either.

  5. I too have a 99 picked up at a yard sale for $10. Looks like it will clean up beautifully but like this one, the motor needs rewiring. Having just successfully resurrected one potted motor for my 15-91 (yesterday!!) thanks to your absolutely fantastic blog series on potted motors, my husband and I are looking forward to doing more (he does the soldering and muscles the reluctant screws and parts and I do the parts cleaning). Rain, I really think you should copyright your potted motor series into a spiral-bound book format and self-publish. I suspect you would have eager buyers everywhere - your photography and explanations are simply outstanding!
    Pat in OR

  6. I also have this machine (just bought it a couple of days ago) and have a question. I'm having trouble with the lower thread looping. I thought it was the bobbin tension, read the manual on how to adjust the screw in the place where the bobbin sits, but it's still doing it. Not huge loops, just little ones. Any ideas on what I need to do? Thanks!

    1. If you have loops on the bottom of your fabric, that is indicative of a problem with the upper tension, and nothing to do with the bobbin. Try tightening your upper tension.

  7. Thank you so much for giving me the courage to rewire my 1962 Singer 99K. The wires on this were a real mess. When I first bought it I thought that I could cover them with some electrical tape and all would be well. But after reading your blog I jumped in with both feet. I even soldered new wires into the light. Just to be sure I took my handiwork to my favorite sewing machine repair guy and he said that I did a great job! You are my new Hero!

  8. Hi, looking at your pics it the same sewing machine i've got. had it a mth or so now going great, then the motor seems to have gone a bit wonky. It seems to be jammed on full speed, thought it might be the pedal somehow jammed but its not that, have you any ideas please..... :(

  9. While they don't cover the electric machines, there is a very good refurbishment manual here:

    We have different standards here in the UK, more volts for a start, and while I am confident of my own skills, things such as replacement motors seem a better bet.