Science of Sewing: Enlarging a Sleeve

Enlarging a sleeve is something I have to do all the time! I don’t have the pencil arms patterns seem to think are normal, so I am constantly redoing the sleeves. I helps that I love a gathered sleeve head, that makes it even easier to alter.

I’m working on a project that requires a rather fluffy sleeve. Having found no such pattern, I decided to make my own using an existing pattern as a base to alter to match. Note that there is some loft in the sleeve head – I’m interpreting that to be gathering. The forearm of the sleeve is also much wider than the bicep, so I’m going to account for that as well.

We’re going to cover just the white portion of the sleeve. The cuff will not be in this tutorial.

Here’s what you’ll need:
Sleeve Pattern (this is from Vogue 9385)
Colored Pencil
Long Ruler
Tracing paper (or medical paper pictured here)

We’re going to do the Slash and Spread method to enlarge the sleeve horizontally. I like the length of the pattern piece, so I’m going to leave that be. Please note that this method will create a gathered sleeve head, not a smooth one.

To slash and spread, I cut all the way through the sleeve pattern pieces vertically, making sure to keep the slashes to the sides of the shoulder seam marking and inside the front and back alignment markings. Putting them on the inside will give me the ability to change the shape of the sleeve head and prepare it for gathering.

Here you can see the cut pieces waiting to be placed to create the final sleeve shape.

As I noted, the base of the sleeve is much wider than the upper portion, so I set the outside pieces at an angle to the center piece. This will create the body I am looking. Also note that the distance between the top and the bottom from the center pattern piece are mirrored. This will create a more balanced sleeve than if you did them unevenly. In this case, the top is 1.25″ and the bottom is 3.25″ in separation.

The last thing you need to do is even out the sleeve head. Because this is gathered, it actually is going to get a flatter profile than the high rounded shape. This is basically a connect the dots: go from the left pattern piece to the right pattern piece, crossing over the shoulder line. You will start and end your line on the size you selected, and the apex of the line (at the shoulder seam) will also go on the size you selected.

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