Singer 15-90 Restoration: Part 4

This post is my latest update for my restoration attempt on my 1948 Singer sewing machine. Here are part 1, part 2, and part 3. So to quickly recap, I have removed all the electrical components on my machine, I have also taken it completely apart, cleaned, polished and put it back together. I don’t think that any part of the machine is especially hard to put back together and so didn’t go into great detail about it, however I am making an exception for the tensioner. I had quite a few problems with it but today I finally squared away the silly thing.

First I haven’t covered yet that after I had the machine cleaned up and back together I oiled it. It is important to oil the machine after a total tear down cleaning because there is (or at least should be) no old oil left to lubricate the parts. Only use sewing machine oil and do so according to your manual.

Okay so to take the tensioner off the machine simply turn the thumb nut like you are adjusting the tension to the left and keep turning until it is off the machine. You can then clean it thoroughly. Here are the components you will have:

The 15-89, 15-90, 15-91 and probably others I don’t know about all have the same tensioner any of their manuals will tell you how to put everything back together, but not very clearly. Here is what you should be starting with:

Here are the two illustrations you will need to put the tensioner assembly back together both from the 15-91 manual (sorry I don’t have my own pictures to go with this, it’s a two hand job):

To begin take the thread guide plate (L) and slide it along the tension rod (N) making sure to slip align the lug (M) into the recess (P). If done correctly the guide plate will not be able to turn. Next slid the tension releasing pin (J) through the middle of the tension rod (N). I found that a small screwdriver works best for this. Next both tension discs (H) are put on the rod with their flat sides together. Place the indicator (G) on the rod with the open side facing out, with the + and – signs facing the sewer. Next is the spring (F) which fits inside the indicator, and the stop washer (D) will fit on top of that with the extension (S) facing out. Then place the numbered dial (C) against the stop washer (D) with number two against the extension (S). Lastly compress the numbered dial (C) so you can screw the thumb nut (A) onto the tension rod (N), before it’s completely tightened slip the pin (B) into on of the holes around the numbered dial.

See, super easy 🙂 After then tensioner is back together, lower the presser bar, and turn to 0, from there you can thread it and test it out. If the proper tension hasn’t been achieved a myriad of adjustments you can make which I won’t online here but can be found in either the 15-89 or 15-90 manuals downloadable for free off Singer’s website here.

My tensioner worked just fine!

This means that my machine is now operational, but still not electrically powered. All the electrical components will be my next hurdle and hopefully part 5 will end with an up and running sewing machine!

UPDATE: How to Clean & Restore Vintage Singer Sewing Machines the eBook is now available in the Zounds Shop! Save and print all of the information you need to fix your machine! 

More to Read!


  1. SJ Chapman says:

    Hi! I have one of these, so I am totally loving your posts! Do you have a manual for it that you could scan in? I am trying to reupholster a couch but am worried if I don’t work it exactly right, I will break it or something!

  2. Laura says:

    You are a godsend! I have a clone class 15 with the tension all wrong, too tight even at it’s limit, and pointed at the wrong number. It looked more or less the same as yours but I figured it must be based on the same principle. I managed to fix it in 3 hours (yes, with patience)….all because you shared your knowledge. Saved me tons from sending to the sewing machine man (who charged $120 spare part plus repair and transport) because the dial looked out of shade and shape. Thank you so much!

    • 3 hours isn’t bad, I think it took me around that long to redo mine, just so many little parts. I’m so glad I could help you out, there is no better feeling than fixing something yourself!


  3. Jeane says:

    I have a Singer clone 15-90. My tension looks different than yours, all chrome, don’t have D stop washer and L plate. What does the tension pin do, mine just falls out when you tip the assembly over. Am I missing some parts here? Excellent tutorial.

  4. Sue Webb says:

    You have the best explanation on how to put this together I have seen, I found lots of diagrams but needed the words to follow. My tension is all clean and back together. Now back to the machine head. What a bugger to clean. LOL

  5. Tokay says:

    Help! Because my tension assembly had years of nicotine buildup on it, I completely disassembled it to clean. I reassembled the tension assembly, but I don’t have a lug M. I notice the thread guide plate L moves back and forth on the assembly. Should it be stationary? What does lug M look like? I don’t see a picture of it.

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