Reverse engineering standard work pt.3

Posted by Kathleen Fasanella on Feb 16, 2006 at 12:29 pm / Patterns, Sewing, Tutorial / Trackback

Today we’re going to cover the patterns for the sleeve finish. These patterns were made from the shirt I showed in various stages of dis-assembly yesterday (list of previous entries at close). I have three patterns, two of which are for the folding jig. The folding jig performs the same sort of function that a folder in the automated sewing process would. If you followed the welt pocket tutorial, you’re already familiar with the wonders you can accomplish with simple paper tools you can make yourself; no expensive tools or equipment necessary.

Anyway, below I’m showing how I made the pattern for the larger portion of the sleeve slit. I’ve taped my draft onto a sheet of gridded plastic so you can pick up the dimensions by printing out the full size piece (1.4MB). This sheet also includes the patterns of the aforementioned paper jig. Notes on that in just a bit.

I want to bring up one issue of notation. You’ll note on this piece that there are cup shaped lines. This is notation that I’ve borrowed from the Japanese and Chinese drafting books. I think it’s useful. Whenever you see these concave notations, it means “divide these points evenly”. I’ve used these markings to note the placement of the center fold line and for the cut out of the piece in the upper right hand corner. The Japanese and Chinese also use other forms of interesting notation that I keep forgetting to write about. And to think my husband worries that I’ll run out of topics. As if.


The other thing I wanted to write about today was the issue of making paper jigs. If you made one before, you’ll already learned that these are not quite as obvious as they seem. For example, below you can see two pieces of this paper folding jig, the inner one is resting easily inside the outer one.

While it may appear to be a good fit, this is no way to test it. To test it, you have to fold the outer jig over the inner one. As you can see below, the inner piece of the jig is too large. It should be resting neatly in the bed of the outer jig when the edges are folded.

Rather, the solution may be counterintuitive. Below is a photo of the jig after I’ve cut away an additional 1/8″ from one long side. It may seem that the inner jig is now too small but then, you still have to calculate an allowance for the fabric (turn of cloth).

People always want an easy rule of thumb to calculate “bend allowance” but it’s just not that simple. Still, there are crude calculations to use. For example, just to get the paper to fit into the outer jig, it’d need a 1/16th reduction. Still, that’s not enough. You need an allowance for the fabric too. I’ve thrown that in as another 1/16th making for 1/8th total. Fabric varies so much so if you’re working with different weights, you’ll have to track that. In some ways, calculating this allowance in leather is easier. I figured out a long time ago that for every ounce of leather (the thickness of leather is gauged by the ounce), I needed to calculate an allowance of 1/16th of an inch. Since garment weights are usually 2.5-3.5 oz in weight, that can make for as much as 1//4″ allowance, give or take fusing.

Anyway, you can print out these pieces, tape them to a manila folder, cut them out and score the lines to fold them. Tomorrow I’ll probably do some sewing but not today. I don’t feel good. I have to go to the doctor. Then I’m going home.

Related:
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

One Response to “Reverse engineering standard work pt.3”

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laurra
March 21st, 2006
9:30 AM

Hi Kathleen,
I made two alterations on my placket jig.
First: I added a center fold line
Second: I cut along the fold lines and sewed them back together using a bridge stitch (univerisal stitch on my burnina) two straight-one horizontal stitch.
I found the jig layed flat so i was able to easily place the fabric in with out to much finessing,folding was easy and crisp.
I borrowed the idea of stitching folding cards from a Carol Duvall Show to work with my jigs.
I wish I had known about jigs when I was working in a DE curtain shop. I was pressing acres of hems. Some curtain fabric tends to be spongey. Im sure a folding jig would have saved the day and cut time in half. laura peace

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