One Piece Underarm Gusset Sewing Tutorial

learn how to insert underarm gusset

How to insert a one piece underarm gusset into a kimono style sleeve.

This is the easiest way and gives neat, sprofessional results.

Follow the diagrams and photographs, read the text… then watch the video. 

The underarm gusset construction  from the kimono style bodice often used throughout the 1950´s is  thought of as difficult and complicated but its really not as hard as it looks.

Practice first on a mock up or two.  The fit of the sleeve is so much better with a diamond gusset its really worth  learn how to fit them.

one piece vintage kimono gusset

 On the pattern there will be a slash marking at the curve of the underarm. Mark this line on the right side of each bodice section, front and back and left and right sides.

Do not cut this line yet.

learn how to insert underarm gusset

Cut strips of fabric to face this slash, approximately 2 inches wide and 1 inch longer than the marking. Pin and baste facing strip along slash marking, right sides together. Stitch, beginning at edge 4mm (1/8)  inch from slash marking and taper to the point. Take one extra stitch across point and stitch down other side.

Not cut the line carefully  to stitching at the point. 

Tum facing to inside and press flat. Pin and stitch underarm seams of bodice and sleeve, matching notches and faced edges ac­curately. Press seam open. Tum bodice to right side. 

This method avoids weak corners and fraying stitches and all your garments look smart and professional.

learn how to insert underarm gusset

The shape of a one piece underarm gusset is usually a diamond or kite shape.

Note that on some Vintage patterns all four sides may be slightly different lengths and will need marking / notching so you position the gusset the correct way around in the garment. 

Edges are best stay stitched because they are cut on the bias.

Once you have practiced inserting a few you can choose how to neaten the raw edges. Pinking, narrow hem, rolled hem or binding. The weight and feel of the fabric determines how to finish the edges. 

learn how to insert underarm gusset

Diagram showing the gusset sewn into position by topstitching the prepared gusset panel. 

Take time to hand baste the gusset in place first rather than try pin. Stitch gusset in position by top-stitching close to faced edge of opening. 

vintage sewing underarm gusset tutorial

This is the paper pattern for the kimono sleeve in the video below.  All 4 sides are slightly different lengths. 

 The inside darkest printed line is the actual size of the hole that the gusset fits into. the middle line is my fold line. The outer dotted line is cut lime for fabric.

Cut a cardboard piece to fit the middle printed line. This pattern gets used alot so having a stiff template makes ironing the gusset edges quick and accurate. 


Fold and glue the paper pattern to your stiff car liner as shown. 

This just makes it simple and easy to press the gusset.

As you notice this pattern is in French, take care to lay the template onto the fabric aligning the fabric bias with the bias line.

Cut out a piece of fabric larger than the template, it  doesn´t need to be exact as will be trimmed after pressing.

Now starch the piece with spray starch until its firm.  Don’t skip this bit!

Top tip: Use 25% cheap vodka to water for a good cheap spray starch that won´t stain darker fabrics. 

The video shows inserting a white gusset into a black garment just to make it easier for you to see. 

The template is marked with water soluble pen here to shw you need to mark one corner so you can keep it correct way up to insert correctly. 



Now you can Fold the fabric edges over the template and press. opposite sides then trim, then the other two sides same and trim. 

With  experience you will have the fabric right side upwards and the edges are ironed so when sewn in place the pinked raw edges are concealed on the inside of the seam. The inside of the garment is as neat as the right side. Dont´t stress for first one if its easier to sew with pinked edges showing on inside of garment.

Use baking parchment or a linen pressing cloth between iron and template to prevent ink / toner transfer from your template. It will last for many garments. 

Follow the video for the next part, inserting into the prepared gusset hole. 

Play Video
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