Here's a quick little tutorial for altering your Iris Tee sleeve (check out the pattern here). This can be used on any sleeve, not just the Iris Tee of course. And what better way to show it than a video? Check the video for a visual overview of the technique, and then read on for all the details and tips.
If you want to be walked through the process, read on for the step-by-step!
You do not need to do this all the way around the pattern, only on the areas that your alteration lines will be hitting.
The seam allowances on the Iris tee are 6mm (¼"), which is perfect for construction with a serger/overlocker, and is standard in the fashion industry for knits.
The alteration lines are a little different for each view.
The three-quarter sleeve
In this case, we are doing a horizontal line across the base of the sleeve crown (this will be perpendicular to the grainline). Then, we will do two vertical lines parallel to the grainline. These should be 1/4 of the way across the sleeve and 3/4 of the way across the sleeve. Using your first, horizontal line as a guide will make it easy.
The short sleeve
We do not need to mark the horizontal line on this one. We can just do two angled lines that go from the hem to the crown.
A standard full bicep adjustment may simply do one vertical line right in the centre, but by using two lines, we can avoid the pleated detail in the centre of the sleeve, while still getting the same effect.
This where the marked seam allowances come in. You only want to cut to just before the marked seam line. Then, make a little clip from the edge of the pattern, to just before the seam line. This will leave a little hinge. This means that our slashing and spreading alterations do not affect the length of the seam, so everything will sew together correctly at the end.
You will want to use your own biceps measurement as a guide. Once you have that, add on a little ease (at least 2cm/¾") so that your sleeve will not be skin-tight. That will be your finished measurement. Open up the sleeve until you reach that measurement.
As you can see in the video, I use weights on my patterns to hold the areas that I do not want to move (the weights shown are large washers from a hardware store. So glam!). For the three-quarter sleeve, the alteration goes down to zero at the hem, as we do not need extra width in the forearm. This means that the sleeve band for this view needs no alterations.
For the short sleeve, the alteration widens all the way to the base of the pattern, as that is the bicep area of the arm. So, the sleeve band needs to be opened up by the same amount added at the hem.
Secure the middle of the pattern piece in the arm area as shown, so it does not move. Then, start opening up the extra width needed in the sleeve. As you do so, you will have to let the centre of the crown drop down, causing the crown height to drop. This makes the shape of the top of the sleeve a little flatter. Basically, we are sacrificing some of the height in the crown to give us more width in the arm.
Lastly, fill in the gaps that have opened up in your pattern with some extra paper, and tape it all down! Make sure there are no bubbles; your pattern piece must sit perfectly flat. If bubbles have formed, keep moving the sections into place until it sits flat. Then, you can smooth out any dents in the outline of the sleeve crown that have formed due to your pivoting. Your new sleeve is ready to cut!
I hope this helps shed some light on this commonly-needed alteration and how it works. You can definitely use this for other sleeves too, not just this design. If you have any questions, or even any requests for other tutorials, let me know in the comments. Happy sewing!
