Modifying a Singer 27 shuttle for a Kayser model L vibrating shuttle sewing machine
When you can’t get parts for an old machine.
I keep mentioning the local repair café - mostly having to do with things I’ve put together to donate as tools. Today’s post is another such object.
Back when we started organizing the repair café, one of the fellows mentioned that he had a couple of old sewing machines in his barn and asked if I’d like to have one. I already have all the sewing machines I need (one for me and two for my wife,) so I didn’t need another. Instead, I volunteered to clean one up for use in the repair café.
Since one of the two machines was a Pfaff model 11 (the renamed version of the Pfaff model K that I cleaned up a couple of years ago,) I decided to take Mae West’s advice (“Between two evils, I always pick the one I never tried before”) and took the Kayser model L to fix up.
The machine itself is very much like the Pfaff K and the Singer 27 that both are modeled on - but it is not identical. That little bit of “not identical” nearly side tracked the whole project.
First off, a look at the refinished machine:
| Kayser model L |
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When I got it, the Kayser needed two things: A serious cleanup and a base to sit on.
The machine was originally in a treadle table, but had been removed so that treadle could be used as a table. I built a base for it and put an electrica motor on it. As with the Pfaff K, this one ended up being made of walnut stained beech wood. The original plan was to make the base of pine, but that fell through. I actually had the pine base nearly finished, then decided to start over with beech because the pine was too soft. Every time I went to work on the pine box, I found another dent in it where I’d bumped it while moving it. That was obviously not going to work, so I made a new box of beech.
The clean up turned out to be a fairly major task all by itself. It was full of fuzzy-wuzzies and old oil, and the shellac finish was ruined. Yes, I ended up stripping the shellac off of another vintage machine - and this time, I didn’t really get away with it. I stripped the shellac off of my Adler model 8 and got away with it because the Adler had decorations made of gold leaf rather than decals. The Kayser had multi-colored decals - mostly gold, but also some red, blue, and green. Stripping the shellac off took the colors off of the decals. Only the silver colored base of the decals stayed put. Everybody that tells you not to strip the shellac with alcohol is right. Don’t do it if you can avoid it.
It isn’t perfect, but it looks much better than when I got it. Most importantly, it won’t get icky stuff all over your cloth - and it does sew well.
Getting it to sew well was the unplanned third part of this project.
There was a shuttle included with the machine, so I wasn’t expecting any problems.
It turned out that the shuttle was from a different machine, possibly the Pfaff 11 that was in the barn with the Kayser.
At any rate, once I had the machine in a usable state I found that the shuttle didn’t fit properly. It was hard to insert and it was hard to remove, the bobbin didn’t like to turn in it, and the thread kept getting stuck.
Having already bought and used a Singer 27 shuttle in a Pfaff model K, I figured I’d see if I could use the same trick on the Kayser. Singer 27 shuttles and bobbins can be bought new on Amazon. They don’t cost that much, which is good because I mangled two before I got the third one modified to properly fit the Kayser L.
The shuttles are one spot where the manufacturers back in the day differentiated. The shuttles are all approximately the same size, as are the bobbins, but there are still differences in the shape, the size, and the fit.
As you can see, an unmodified Singer 27 shuttle doesn’t quite fit the Kayser L:
| Un-modified Singer 27 shuttle in the Kayser L |
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- The open end where the bobbin goes in doesn’t fit the spring at the end of the shuttle carrier.
- The notch in the pointed end of the shuttle isn’t big enough for the spring in the shuttle carrier.
The first point is fairly easy to solve. Just grind the open end on a slant so that there’s space for the spring.
| Grind the open end |
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The one trick here is that you can’t grind too deep. That’s how I ruined one shuttle. I ground it below the brass part of the bobbin (red line.) The bobbin would drag on that edge, making the shuttle useless - the bobbin dragged so bad it could barely turn.
- Grind following the blue line.
- Stay above the red line.
The notch in the pointed end was harder to fix. First I fixed the open end so that the shuttle would fit the carrier better, then I put the shuttle in and marked where the notch needed to be.
| Marking the notch |
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The shuttle already has a notch, but it is for a Singer, not a Kayser. The Kayser hold down spring is much wider, although it is about as deep.
I used a diamond wheel in a bench grinder the widen the notch. Work slowly. Grind it a bit, then check the fit. See where it needs to be ground down more or where you are deep enough. It will take several rounds of grind and check to get it right. When in doubt, stop grinding too soon. You can always remove a bit more later, but if you remove too much the shuttle will flop and bounce around - you’ll have to start over with a new one.
Once the notch is deep enough, you’ll want to smooth it with some fine sandpaper, then polish it with a buffing wheel and some polishing compound. The notch has to be smooth so that the thread won’t drag. There should not be and sharp edges, either. A sharp edge can cut the thread.
Warning: too tight is better than too loose at this point. You still have to grind the shuttle to fit the shuttle race. That will change how the notch and the hold-down spring fit together.
The finished notch looks like this:
| Finished notch |
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Once you have the notch fixed, you need to grind the shuttle shape.
The “heel” and “sole” of the shuttle rub on the shuttle race. The shuttle and the race have to be in contact to keep the thread from getting trapped between them, but if the shuttle shape is wrong then the shuttle (made of hard steel) will wear away the race (soft iron,) ruining the machine over time.
I’ve mentioned grinding the shuttle before, and gave some tips.
Here are a few more:
- I used a permanent marker to see how well the shuttle fit the machine. Paint the “heel” and “sole” of the shuttle with the permanent marker, put it in the machine and run it a few seconds at medium speed. The friction rubs the ink off, showing where the shuttle needs to be ground down.
- The shape is part of the problem (the curve of the shuttle race.) The other thing is the overall length of the shuttle. If the shuttle is too long, then you have to grind if shorter. You can only shorten it by grinding the “sole” of the shuttle. That’s the curved side on the pointed end. You can’t simply grind the open end to shorten the shuttle because that shortens the cavity for the bobbin. The bobbin will not fit anymore.
- I used my diamond grit sharpening stones to grind the surfaces. I used the 120 grit to shape the shuttle, then worked up to the 3000 to make it smooth. After that, I used the buffing wheel with polishing compound to make the shuttle mirror smooth.
| Grinding the shuttle |
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You keep painting the shuttle, running it, and grinding down high spots until you get an even wear pattern across the heel and sole. That is, running the machine with the shuttle in it should wear the black ink off evenly like in the second picture there.
Once you get the wear even, load a wound bobbin in the shuttle, thread the machine, and sew stitches by hand cranking the machine (do not use the motor.) The idea here is to watch and listen as the upper thread passes beneath the hold-down spring at the point of the shuttl.
The upper thread should pass the spring without catching (you should not hear a “bink” from the spring) and without making the shuttle jump (no “clank.”) A “bink” means the thread has a really hard time passing under the spring - the shuttle is still pretty far off correct. A “clank” is getting closer to correct. The shuttle pops up and down a little when the thread passes through.
In the video, the shuttle is still “clanking.” That means I need to grind it some more. Maybe on the sole, maybe in the notch. It is a balancing act. If I had a proper shuttle, I wouldn’t have to grind the notch at all. Since this is a Singer shuttle, I have to find a balance between the depth (and width) of the notch as well as the shape and length of the shuttle.
If the shuttle binks or clanks, then you need to grind the heel and sole some more. Make sure to grind them evenly - continue using the permanent marker to check for high spots.
With the shuttle modified and fitted, the Kayser L sews again - after who knows how many decades.
You may notice that the Kayser has a reverse function. As best as I can tell, the Kayser L was manufactured before 1931. The Singer 15 didn’t get reverse until like 1950. The German made machines started including reverse decades before Singer.
I used the Kayser to sew a new zipper into a pair of blue jeans as a final test. After a couple of months of use, the zipper is still in place.
Did you know that the waist of a pair of blue jeans is sewn with a special chain stitch sewing machine that sews two seams at once? I didn’t know that until I went to replace the zipper. I noticed the chain stitch, then discovered later that the blue jeans makers use a special machine that sews multiple seams at once. The Kansai Special DLR series is an example of such machines.