The assembly of a pair of jeans is very different from the usual way of sewing together the legs of a pair of pants. However, the result will look really professional and be very sturdy, the only downside is that it’s nearly impossible to fit the jeans as you sew, so make sure they fit properly before you embark on this adventure.
Tools for sewing yoke and side seams
- Serger or a sewing machine for overcasting the fabric edges
- Topstitching thread
- Edge presser foot
- Jeans or topstitching needles
Primer for overcasting
- For seams being topstitched: Overcast both layers after the seam has been sewing together to save time and avoid bulk (for instance the crotch and yoke seams)
- For seams being pressed apart: Overcast each layer separately before you stitch the seam together (usually the outer seam)
- Overcasting on a serger: Use the wide 3-thread overlock or the 2-thread flatlock seam
- Overcasting on a sewing machine: A slightly wider zigzag stitch will work nicely
Denim overcasted with a wide 3-thread overlock, which is the standard in the denim industry.
Choosing which side seam to topstitch
For ease of construction, you need to choose between stitching the outer or inner seam. Here are how some big brands are doing it (though it might vary between styles too):
Topstitching the inner seam: Lee, Levi’s, Nudie jeans, True Religion, Calvin Klein
Topstitching the outer seam: Wrangler
Sewing the yoke
1. Stitch and overcast each yoke separately before sewing the crotch seam
2. Topstitch the yoke seam
Fold the seam allowance downward and topstitch two rows. For topstitch instructions see: How to sew perfect topstitching.
Sewing the side seams
1. Sew the crotch seam
Lay the back pieces together, right sides facing and sew the crotch seam a regular straight stitch. Overcast the seam if you haven’t done it already
2. Topstitch the crotch seam
Turn the back pieces to the right side. Fold the seam allowance to the left, and topstitch the crotch seam to reinforce it. I used two rows. Tip: Use a hump-jumper to elevate the presser foot if you find it hard to stitch over the bulky crotch seam intersection.
3. Sew the side seam you intend to topstitch.
In this case, I’m doing the inseam. You sew from one leg opening to the other in one continuous seam.
For instance, start at the left foot opening and don’t stop until you have hit the right foot opening. Just make sure that the front and back crotch seam is aligned.
4. Prepare for topstitching
Fold the seam allowance towards the front, this is the most common way to do it in the jeans garment industry.
5. Topstitch the inseam
Stitch all the way from one leg opening to the other one. Use a hump-jumper if you are having problems stitching over the bulky crotch seam. The second row is optional. See How to perfect topstitching for detailed instructions for topstitching jeans.
6. The inside of the seam.
For best result always use regular sewing machine thread in the bobbin as thick thread might jam up in the bobbin.
7. Sew the outer seam
Sew both outer seams using a straight stitch.
8. Topstitch over the pocket
Fold the seam allowance to the front. Edgestitch on the front piece close to the outer side seam and secure the seam properly.
Now the side seams and yoke are done!