Reverse engineering standard work pt.4

Continuing with the fourth in this series (see the list of entries at the close of this entry), we’ve almost reached the construction portion of the sleeve slit. However, there’s still some make-ready to do. By that I mean we need to implement those jigs I made in part 3. Before I do that though, it occurs to me that I should show you how to score a fold line of a jig. Below you’ll see me scoring a jig fold line with the business end of a protractor. The pointy tip is just dandy for this sort of thing. If you’ll note in the photo below, I’ve weighted the ruler down because the pressure I’m plying against the edge of the ruler will cause it to shift otherwise. It’s hard to hold a ruler, protractor and apply even pressure without a weight to hold the ruler in place.

Now it’s time to press the fabric pieces to fit the sleeve slit. This of course, is a departure from automated standard work because in automation, you’d have a folder that would shape these pieces as they were fed into the machine. Now, just because you don’t have a folder doesn’t mean you can’t cannibalize the automation process to get the same result -which is the point of this exercise. As you’ll see tomorrow, copying the moves of the automation process will save you some sewing and time. It’s also easier. Below I’ve pressed the larger portion of the slit using the jig.

Below you’ll see that I’ve pressed both pieces:

The next step is to fold each of these pieces in half along their lengths. The finished work is shown below:

Now that these pieces are ready, you have to make sure your sleeve is set up to receive them. Below I’ve shown a picture of what the pattern for the sleeve slit looks like. You’ll notice that the end of the slit is marked with a circled punch.

Now before you want to do anything else, you’ll want to make sure your sleeve slit pieces are the correct length. Below I’ve shown mine:

Now, again we’re forced to depart from the automation process. We don’t have a machine with laser sights that will find the end of the slit for us. We don’t have a die that will automatically cut the triangle at the end either so we need to do that. Below you’ll see that I’ve marked 1/4″ off to either side to indicate the ends of the cut triangle.

Now I’ve cut the slit, stopping about 1/4″ shy of the very end.

Now I’ve drawn a line, joining these two pencil points.

With this marked off, I’ve cut the triangle. I know this kind of stuff worries people. It does me too sometimes and I haven’t sewn a shirt like this in years. Don’t worry. It’ll come out okay. Besides, you’re using scrap pieces, right?

Here I’m showing the reverse side with a line drawn across too.

Below I’m showing a picture of a die that I have for a “smiley” pocket that you’ll see in western wear sometimes. I’m showing it so you can see the triangle cuts on each end of the die.

Using a die is one way you can automate the process for precision cuts. Still, you can make a pattern piece with a cut out to trace out the triangle shape which will save you the time of having to mark a bunch of sleeves with a ruler. I think the best way to do this whole triangle cut out thing is to just cut the slit part of the way up -like I showed you- and then to have the operator clip those marked corners just before they start sewing or just before they hit those corners. I haven’t figured out which way is best but I’m leaning towards cutting the triangle, then sewing. Also, I don’t think it’s a good idea to precut all of those triangles beforehand (when the sleeves are cut) because fabric frays when it’s handled. I think cutting those triangles should be done on the spot, just before it’s needed rather than when the long slit is cut.

Anyway, get all your stuff ready. Tomorrow I’ll show you how to sew it. Also, since I’ve already done mine, I can tell you another downside in advance. When forming the triangle top of the large fabric piece (shown below),

I had to fiddle too much with it to get it even. I’m thinking you’ll be better off pressing that into its final shape ahead of time -before you start sewing. Pre-pressing that top piece will be faster and more uniform than doing it on the spot if you’re an inexperienced operator. At least that was my experience.

Entries in the reverse engineering standard work series (how to copy industrial sewing methods)
Shirt making tips
Standard Work (sounds boring, read it anyway)
Reverse engineering standard work pt.1
Reverse engineering standard work pt.2
Reverse engineering standard work pt.3
Reverse engineering standard work pt.4
Reverse engineering standard work pt.5
Reverse engineering standard work pt.6
Reverse engineering standard work pt.7
Reverse engineering standard work pt.8
Reverse engineering standard work pt.9

Spin off of Reverse engineering standard work pt.5:
A failed experiment
A failed experiment pt.2
A failed experiment pt.3
Reverse engineering standard work pt.5.1


  1. Sheryl says:

    Enjoying reading this adventure, as I did exactly the same thing years ago!
    I usually clip the triangle after attaching one side of each binding first – this allows for little inaccuracies! Then I manually bind the edges, haven’t read the next part yet but I guess having prepressed you will bind in one action?

  2. Elizabeth says:

    I am so very grateful for your tutorials. I am a mother on budget who wants to make stylish clothing that looks good..not to mention sewing had become my new found passion. So again thank you so much

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