How to Insert a Triangular Gore into a Slash

This tutorial walks you through two different methods of inserting a triangular gore into a slash.  This kind of construction is sometimes seen in modern and vintage garments, and it is commonly used to define bust shape in women’s undergarments throughout the 1800′s.  The images used to illustrate were taken while I was constructing a mock-up for a Regency era corset.

The first step in any sewing endeavor is to transfer all your marks.  When you are going to be inserting gores into a slash, mark the end point of the slash, the slash line, and the seam lines.

It is usually easiest to mark the end points and the seam points first.

And mark the lines using a ruler.  Here I am using a pencil because this is a mock-up and I don’t care if the marks show.  You can use chalk or whatever marking tool you prefer.

It is also important to mark the gore(s) so you can tell where they go and how they should be oriented.  This regency corset has two gores on each bust, so I marked the inner one “A” and the outer one “B”.  The dot indicates where it matches the apex of the slash, and the arrow points towards the center front.  Here they are photographed below their corresponding slashes.

While not technically necessary, I strongly recommend stitching close to either side of where you will be cutting the slash.  Back stitch along the stitch lines at the apex of the slash.  This helps to prevent fraying and reenforce the fabric while inserting the gore.  If you like, you can also use a bit of fray check, but if you do so be very careful of it discoloring any material which might be visible in the finished garment.

Wait to slash each gore until you are ready to sew it.

First Insertion Method

Or, Two Seam Insertion Method

This method starts at the apex of the slash, and sews each side of the gore separately.  This is the method I prefer to use with heavier materials, like coutil.

Cut your gore slash.

With right sides together, match up the dot on your gore with the apex of the slash.  Insert your sewing machine needle at the apex.  Stitch forward and backward a couple times to secure, being very careful not to back up beyond the apex.

Stitch the seam, keeping the gore at seam allowance and following the seam line for the slash.  Back stitch to finish at the edge of the fabric.

This is what your gore should look like after finishing the first seam.  The stitch should follow the seam allowance from the dot to the top edge of the gore.  The body of the gore should be right-sides together, with the bulk of it away from the slash.

Turn the gore so the seam is open, pulling the seam allowance of the gore at the bottom of the slash from the right side to the wrong side of the garment.

Fold over the panel of fabric so you are looking at the second seam, right sides together, with the gore underneath.

Start at the apex of the slash like you did for the first side, and stitch to the edge of the gore.  Be sure to follow the stitch line and keep the gore at seam allowance.

Open it out, and your gore should look something like this.

Second Insertion Method

Or, Single Seam Insertion Method

This is the kind of method I have seen most often described in sewing books and pattern instructions.  It involves sewing the gore into the garment using one continual seam from outer edge to outer edge.  This method is much faster, so I prefer to use it with lightweight fabrics.

Cut your gore slash.

Start your seam at the top of the gore with right sides together, panel at the seam line, and gore at seam allowance.

Stitch to the apex of the slash, keeping the gore at seam allowance and following the seam line of the slash.  Back stitch a couple times to reenforce, but be careful not to stitch past the apex of the slash.

With the needle inserted at the apex of the slash, lift your presser foot and turn the garment so the gore is oriented towards you.

While holding the gore in place, pull the bulk of the fabric around so that you are looking at the two edges of the seam.

Pull and adjust the gore and the bulk of the fabric until it is laying smoothly to the side and you can clearly see the edges of your seam.  If you were careful not to stitch past the apex of the slash you should be able to get it almost completely smooth.  This is more difficult with heavier fabrics, which sometimes refuse to get out of the way.

Back stitch a couple times at the apex to reenforce the area, and then stitch to the other end of the gore.  As before, keep the gore at seam allowance and follow the seam line of the slash.  Back stitch when you get to the end of the seam.

Finishing the Gore

Regardless of which method you use to insert the gore, you will want to finish it so it lays smoothly and does not pull free.  All gores inserted into a slash are prone to pulling free at the apex because of the miniscule amount of seam allowance required to smoothly insert the gore.

At the very least, you will want to edge stitch around the entire gore, adding a few extra reenforcing stitches at the apex.  If desired, you can also add some decorative machine stitches over the apex area, or include some embroidery at the apex to hold it firmly in place.