How to Make a V-Neck Insert

Cut around the neckline of the T-shirt with sharp fabric scissors and remove the rib collar. Save the collar for another project.

Measure the midpoint of the front collar with a flexible tape measure. Mark the midpoint with tailor's chalk.

Position a ruler vertically at the midpoint to measure the desired length of the V-neck, referred to as the neckline depth.

Cut a vertical slit at the midpoint of the collar using the dimension from the previous step.

Spread the V-neck until you are satisfied with the V-neck opening. This is the width of the V-neck, referred to as the distance or spread. The fabric insert is placed in the opening in a later step.

Position your ruler horizontally on pattern paper. Draw a line using the distance measurement from the previous step with a drafting pencil or thin-tip felt marker.

Position the ruler vertically at the midpoint of the horizontal line. For instance, if the V-neck distance is 3 inches, position the ruler at the 1½-inch center point. Draw the vertical line using the V-neck depth measurement from Step 3.

Draw the V-neck shape by connecting the two outer points of the horizontal line with the vertical line. The V-neck pattern appears, resembling an upside down triangle.

Add a ½-inch seam allowance around the V-neck pattern insert. You need the added allowance to serge the insert to the T-shirt neckline.

Cut out the pattern with paper scissors. Pin it to the selected insert fabric such as jersey or Lycra with straight pins.

Cut out the V-neck fabric insert with fabric scissors to avoid jagged raw edges.

Pin the V-neck insert to the T-shirt opening made in Steps 4 and 5.

Measure the depth and distance of the premade lace V-neck insert with your ruler.

Repeat Steps 2 and 4 from the previous section to find the neckline's midpoint. Use the length measurement from the previous step in this section for cutting the vertical slit.

Spread the V-neck opening using the distance measurement from this section's Step 1.

Change the sewing machine's stitch selector wheel to a long stitch.

Stitch a stay stitch around the T-shirt's V-neck area with the long stitch. Use the edge stitch foot attachment to guide the stitch close to the raw edge. This step ensures the V-neck does not continue to spread while stitching the insert.

Pin the fabric insert made in Section 1 or the premade insert from Section 2 within the stitched V-neck area. This step is a bit tricky because the V-neck has a stay stitch, which reduces flexibility. Make sure the raw seams are facing the wrong side of the fabric.

Serge the pieces together with a serger machine. If your serger has a knife to trim off the raw edges, take extra time as you approach the V-point. The knife can cut an unwanted angled slit through the V-point and into the fabric. Another alternative is to use an overlock machine, using an overlock stitch. This process adjoins the T-shirt body and V-neck insert using the flat overlock stitch for a clean finish.