We’ve translated Japanese brand Workers’ six part feature on the denim production process From Cotton to Jeans. In Parts V and VI, they discuss the pattern creation and sewing stages. Click here to start from the beginning.
This is the pattern for a pair of selvedge jeans. As you can see, the outer edge is completely straight, since it’s made with the selvedge end of the fabric. The angle of the hem is also straight, so there are only six lines available for shaping the silhouette: the inner thigh, the center line, the lines of the front and back rise, the back of the waistband, and the bottom line of the back of the jeans.
The pattern is created by shaping these six lines. The function of the yoke is to simplify the change in lines. It’s possible that this reduces the amount of fabric necessary.
This time, we’re making two types of jeans: the 801 Straight Fit and 802 Slim Tapered fit. Comparing the two fits above, and editing out the stitching and pockets, you can see that the fit on the left is the 802 Slim Tapered, and the 801 Straight is on the right.
First, the 802 has a lower rise than the 801, and the 802 also has a slimmer hip and thigh, emphasizing a slim, fitted silhouette. In contrast, the 801 has a looser, more relaxed fit, which leads to a looser, more vertical pattern of whiskering on the lap. The 802 has an attractive appearance for standing, while the 801 is well-suited to working and other active movement.
The picture above shows the pattern used for cutting the denim into the parts used in constructing a pair of jeans. The design on the left is used for rolls of selvedge denim 86 cm wide, and requires a length of fabric about 2.6 m in length. The design on the right is used for a modern, non-selvedge fabric 150 cm in width. In other words, making selvedge jeans requires the use of a fabric that is only about half the width of a modern roll.
This fabric is loomstate, meaning that it has not been processed or pre-shrunk after weaving. Once we calculate the rate of shrinkage, we take that into account in making the pattern shown above. For example, the main part of the leg is aligned vertically, the yoke horizontal, the waistband vertical, and other parts depending on their type. We have to study and modify the fit based on the resulting shrinkage after the jeans are sewn, washed, and dried.
On this particular pair, as you can see above, the fit is a bit too loose in the rear, and the top of the thigh and rise need to be slightly adjusted to remove this effect. The effort involved in modifying the fit to compensate for shrinkage adds to the labor involved in creating loomstate jeans. The fit, creasing patterns, and shape of the jeans often need to be further modified and corrected by adding or taking away length in various places on the pattern.
A characteristic of designing selvedge jeans is lining up the selvedge edges. As shown in the picture above, all of the selvedge ends of the denim are put together, and on top of the fabric the pattern is placed for the cutter to follow.
The fabric is almost 86 cm wide, but there may be variation of a few millimeters. Because of that, after half of them are cut, the selvedge lines are lined up again before cutting for the other side of the jeans.
Folding, Waistband, and Hem
One characteristic of sewing jeans is that each process uses a specialized sewing machine. Here we’ll introduce felled seam sewing. Originally, this process and its specialized machine were used in order to increase efficiency, but it’s also the source of the roping effect gives jeans their unique character.
Since each sewing machine sews with a chainstitch, the bottom thread doesn’t wind the bobbin, and it’s not necessary to wind each thread for the bobbin.
The Union Special 43200G is a sewing machine dedicate to sewing the hem of the jeans. For people who love jeans, it creates the familiar roping shape at the hem. However, this machine is not a multipurpose model and depending on the materials, a different model of machine might be used. The sewing machine is selected in order to suit the material.
This is the button attachment. The modern way involves using an Auto Belter to cut the loops to the designated length, folding, and then fixing on the button. However, our jeans are made the old-fashioned way, where the loops and buttons are attached be separate machines. The buttons are fixed using a laser pointer to pinpoint the correct place.
That concludes From Cotton to Jeans, we’ve now seen it all! You can learn more about Workers and their products via their website.