Monday, September 19, 2011

Bad Wiring? Save the Terminal Plug Before You Trash It

As every vintage sewing machine hunter knows, a lot of times you buy a machine and the seller insists you take the cabinet it's mounted in, because they just want it out of their garage. The first few times that's fun--hey, free desk!--but soon you have more cabinets than you know what to do with.

If you have a Singer that's been wired for cabinet use, it will have a "single lead" power cable with just one set of wires going into the terminal plug. Here's the one from my latest acquisition:

As you can see, this one's in poor shape and needs to be tossed. The wiring insulation looks like it dates to the Eisenhower administration and you can see bare metal. But before we get rid of it, we're going to "harvest" the Singer terminal plug, so that later we can easily--and inexpensively--make ourselves a new power cable.

This here's the terminal plug. It's got two screws holding it together and is super-easy to get apart.

A Brownells bit #150-4 fits the screw perfectly. (Click here if you need to learn about screwdriver bits.)

As you loosen the screws, be aware that the little nut on the other side may fall out of the bottom.

So do it over a towel or carpet scrap, so that the nut doesn't fall out and bounce onto the floor, causing you to get down on your hands and knees with a flashlight trying to find the darn thing. (Yes, that's what happened to me the first time.)

Once you've got the screws removed, the two halves come apart and you see this:

Looks intimidating but it's not. All it is is two wires going into two little brass connectors. There's a third brass connector in the center, but this will be empty for a cabinet-wiring configuration.

The brass connectors just pop right out.

Then you can just unscrew the knurled brass ring, revealing the wiring wrapped around the threaded part.

That wiring pops right off.

Then, do yourself a favor and screw the knurled brass ring back onto the connector before you lose it. Next, cut the wiring outside of the terminal plug and push the remaining wiring through the plug to remove it.

I'm actually going to save this cut-off scrap of wiring, so that later, when we replace it in a future entry, we can copy the knot they used to hold it in there.

After you've removed the wiring, put all three brass connectors back into the plug body.

Then just screw everything back together for safekeeping.

What Not to Do: As you first begin turning the screws, turn them slowly to be sure they're entering the nut at the proper angle. The first time I did this I was in a hurry to get it back together and accidentally forced the screw in at a slight angle. This stripped the end of the screw and ruined the threads inside of the nut, rendering both parts useless. So even though this is a simple little procedure for a simple little part, take your time with it. What I've found in sewing machine repair is that patience is everything; those times that I've rushed something is always when I damage a part or strip a screw.

To turn this into a new, working power cord, you can order the cables with a molded plug right here from Jenny at Sew-Classic, my favorite sewing machine parts supplier. It's only $3.29, versus the $8.69 you'd pay for the molded plug, cable and terminal plug. (She also stocks those right here, by the way.) Not a huge price difference, but if you order just the cables and wire it into the terminal plug yourself, you get the satisfaction of keeping one more piece out of the garbage and back into service. Plus the original Singer terminal plugs have that neat "S" on them.

Just two more things:

One, what I've been referring to here as the "terminal plug" is called, in Singer's original manuals, the "3 pin terminal, female half," just FYI.

Two, I typically drop my bad wiring off at a local recycling center rather than throwing them in the trash. An electronics recycler will take the time to harvest the metal in the wiring and turn it into something useful. If you have a Best Buy near you, they accept old electronics and wiring for recycling free of charge.


  1. Thanks! Wiring is the main thing that intimidates me about working on these old machines and you just gave my confidence level a boost!

  2. Good idea about recycling the wire. We've been looking for "vintage" flat insulated wire to keep true to what they used to use (vs the zip wire, lamp wire that's readily available in stores). Can't wait for your next post to see if you talk about that aspect of rewiring.

  3. Thanks, Rain. I wish I had this information before I tried to take one apart the first time. Darn thing just about exploded tiny parts. I still haven't found 'em all.
    Great clear photos. thanks!

  4. Thanks Rain. Another idea is to buy an extension cord and cut off the female end and wire it to the three pin terminal, female half. Of course most extension cords are either brown or white, not black, hence the advantage of buying from Jenny at Sew Classic. And she has FAST and inexpensive shipping I might add.

  5. You make it look so simple!! I'll give it a try. I have to laugh about your comment concerning having too many! Lately I have been ignoring any CL ads that have a machine AND the cabinet.

    Also, I wanted to say thank you for recommending the Maas Metal Polish, in an earlier post. I ordered some and got to use it for the first time, yesterday, on a vintage machine that I'm cleaning up for a friend. I can't believe how wonderful it works!!!

  6. someone on ISMACS justpointed me to They have the old style wire that I have been looking for. Really enjoying your blog!

  7. I inherited a lovely Singer Featherweight from my Grandma a couple of years ago. It has the beautiful stitch that the Featherweight is known for. When I got it, the cord looked like it had been chewed by rats--a lot like the one in your picture. I had a repair shop make a new power cable for me. Never thought it was something I could do on my own. Now I have another problem though. The pin that holds the bobbin for winding bobbins doesn't spin when it is in the bobbin winding position. It's just very stiff. I can turn it by hand (slowly), but of course I can wind the bobbin faster by hand without turning it that way. Is there some way to loosen that pin so the bobbin will wind?

  8. Wow, these are excellent pictures. What a great, detailed post. I've always thought of the power chord being quite difficult. Thanks for the great post Rain.

  9. This was a great demo, thank you. My cord of my mother's singer was needing replacement. We went to a singer parts store..they gave us one and said to bring it back if it didn't work. It didn't, and we are very happy by doing just as you showed us. Now safe again, a slightly longer cord that I wished for. Save that terminal by all means. :)

  10. My wife picked up a vintage Singer machine serial # AJ087104, circa 1940-41 based on the last date in the booklet. Not sure of model number. The power cord is bad. Unlike your example, it is completely rubber encased with no screws to take it apart. Should I just drill two holes for screws and then hacksaw it in two lengthwise to make my repairs before bolting it back together with news bolts and nuts?
    Tampa, FL

  11. Paul, I wouldn't recommend it. My advice would be to simply order a new cable from Sew-Classic.

  12. You have been most helpful. Used your guidance to rewire the old terminal tonight. It looks good!