For this tutorial, you’ll need to have the Trillium (formerly Washi) Sewing Pattern. You can find the pattern in my shop! The free sleeve pattern piece is available via email, which you can sign up for below.

Since we updated the size range for this beloved pattern (formerly known as Washi), I’ve had many requests for an updated Expansion Pack. Many of you specifically requested this sleeve.

As you may already know, the Expansion Pack was a supplement to the original pattern that included pattern pieces for sleeves, bows, and collars, a bodice lining and elastic casing (for those who prefer it to shirring). One of the pattern pieces was a gathered long sleeve. While I may eventually package up and sell an updated expansion pack again, in the meantime, I decided I would offer some parts of the Expansion Pack as free downloads and/or tutorials for a limited time from my website.

In this post, I’ll show you how to add a gathered sleeve to your Trillium Dress or Top. This tutorial is an add-on to the pattern, so first you’ll need to assemble your garment up to the shoulder seams. Once you’ve done this, you’ll add the sleeves as shown below.

Notes:

I suggest adding an additional 1/4 inch [6 cm] seam allowance along the armholes to create a wider seam allowance for adding the sleeve. This can be done while cutting out your fabric, or just add it while you’re tracing your pattern pieces (see also: How to Trace a Pattern)
If you’re also lining your dress, you may want to take a look at this original sleeve tutorial post for some additional hints on adding a lining along with the sleeve. For the Trillium bodice lining videos, click here.

You will need:

free Trillium Sleeve PDF download (sign up below to get the file via email)
for the cuffs: two pieces of 1/4 inch [6 mm] wide elastic
3/4 yds [0.7 m] of additional fabric for sleeves
tools: sewing machine, pins, scissors or rotary cutter, safety pin or bodkin

Let’s get started!

PRINT AND ASSEMBLE YOUR PATTERN PIECE

It’s six pages, and you’ll need to tape it together by trimming the edges and matching up the circles. Don’t forget to DOUBLE CHECK THE SCALE SQUARE!

CUT OUT the SLEEVE PIECES

Place folded fabric on a flat surface with the fabric selvages parallel to the fold.

Cut two SLEEVE pieces on the fold (note that the pattern piece has an option to add extra width at the center for the C/D bodice if you would like; you can get creative and add more width here for a super fun puffy sleeve!). Transfer notches.

Optional: For a fuller sleeve, add width by sliding the pattern piece away from the fold.

SEW THE SHOULDER SEAMS

Follow the instructions in your Trillium pattern. Once you have sewn the shoulder seams to attach the front and back, it’s time to attach the sleeves.

gather sleeve caps

With your machine set to the longest stitch length possible and tension set to high, sew two lines of gathering (basting) stitches 3/8 inch [10 mm] and 5/8 inch [16 mm] away from the top edge of the sleeves between the notches, then pull the top threads to gather.

attach sleeves

Pin the sleeves to the armholes with right sides facing, and adjust the gathers to fit the armhole. Sew sleeve to armhole with a 1/2 inch [13 mm] seam allowance. Remove any visible gathering stitches, and finish seam as desired.

If you are including a neckline facing, complete those steps now, then come back to sew your side seams.

Sew side seams

Place front and back together with right sides facing and pin along the side seams of both the sleeves and the body of the garment. Sew side seams with a 1/2 inch [13 mm] seam allowance from the ends of the sleeves up to the armhole, pivot at the underarm, and proceed down the side seam.

Sew the cuffs

Press under 1/4 inch [6mm] toward the wrong side along the bottom edge of each sleeve and then fold and press another 1/2 inch [13 mm] under. Stitch along the first fold to form a casing, leaving 1 inch [2.5 cm] open for the elastic.

Alternatively, if you prefer sleeves without elastic: you can sew the entire folded edge (skip adding the openings) to hem and finish the sleeves.

Cut two pieces of 1/4 inch [6 mm] wide elastic to the length needed. Find this length by measuring around your forearm where the sleeve will hit (try your garment on!), and adding 1 inch (2.5 cm).

Using a safety pin or bodkin, thread a piece of elastic through each cuff, pin the ends together with a 1/2 inch [13 mm] overlap, then try the garment on to adjust for comfort. Stitch back and forth through the overlapped ends to secure the elastic. Stitch the casing closed.

Then use the pattern instructions to hem and finish your garment!

Share your Trillium makes online and see what everyone else is making using the #MBRTrillium tag! I love to see what you’re making with this pattern.

Still need the dress pattern? You can find the Trillium pattern in my shop, and check out the Trillium page for more tutorials and resources for this pattern.

How to add a long sleeve to Trillium (+ FREE PATTERN PIECE)