In this post, we're going to take a look at doing a full bicep adjustment on a set-in sleeve. Signs you may need a full bicep adjustment are that the armpit of your garment is uncomfortably high and/or the fabric is stretched too tightly around your bicep. Rivet has a bicep measurement on the size chart, and we also give finished bicep measurements in our patterns. We do this to give you solid numbers to base your adjustments off of. If the pattern you are working with does not include these measurements, you'll need to flat measure your sleeve piece to determine your adjustment.
To measure your bicep, make a 'Rosie the Riveter' type move and measure the fullest part of your bicep.
If you would like to follow along with me in a video, you can do so in our Full Bicep on a Set-in Sleeve YouTube Video.
On the fly:
This adjustment is 100% NOT the technically correct way to do it. I probably shouldn't even mention it, but if it works for you, it works. You never want to do this a woven sleeve, and it can be hit or miss with super fitted sleeves. However, it does have its advantages when you have a small adjustment you need to do quickly. All you're going to do is gently curve a line from the under arm point to the fullest point of the bicep, and then back in again for the elbow. For example, I typically make a Rivet size 8, but my bicep is in a size 12.
It looks weird and isn't correct, but it comes in handy sometimes! Now let's move on to the actual technique.
Correct Technique:
First, you're going to draw in your seam allowances all around the sleeve. You will also mark the top of the sleeve cap (if your pattern does not have a notch). Next, using your straight ruler, draw a vertical line from the notch to hem. Draw a second line horizontally across the bicep.
Now we are going to cut. Starting at the hem, cut vertically all the way up the sleeve. Stop when you get to the seam allowance. Next, cut the horizontal line from the center to the side seams, again stopping when you get to the seam allowances. To make each of these three points into hinges, cut into the seam allowances. Cut to, but not through, the seam allowances where you ended your initial cuts.
Now we've got all sorts of movement at the hinges! We're ready to make the adjustment. Gently push the bicep line outwards on each side. As you do this, the top and bottom will overlap at the bicep line. Keep the hem centers together.
Place a piece of paper behind your pattern piece, and trace around the perimeter of the sleeve. Almost there! The last step is to even out the dip at the sleeve cap and the hem. Gently round out the top of the sleeve cap, and use a straight ruler to redraw the wrist line.
You'll notice that when we made this adjustment, it flattened the sleeve cap. In many patterns, this won't affect the final garment. However, in some instances such as a fitted sleeve with little vertical stretch, you may need to add the height back into the sleeve cap and adjust the armscye to match. I address this in the VIDEO at minute 10:00.
Otherwise, that's IT! You're all done. That wasn't too hard, was it?