A23 PUFF SLEEVE

Now let's tackle those sleeves.
We are going to take the side we did not cut diagonally. The side we cut off straight. We are going to fold it down approximately half and inch. Press down.
Then fold it again another half and inch. Press down. You will fold and fold, kind of like rolling up the sleeves. You know you did it in the eighties. You know you did. Well, this is just backwards from that.
Then press again. Make sure your sleeve is not inside out. Make sure it is inside right. It should be fine if your children haven't played with it since you cut it out.
Then sew a straight line along the edge of the sleeve to secure the hem. I sewed at a 3/8" seam allowance. You are sewing in a circle. When you come back around to where you started be sure to back stitch. Then clip your threads tight.Do this to both of your sleeves.
There you have it. Both of your sleeves are hemmed.
Now we are going to use elastic thread to pull the hem in tight against our arm. Elastic thread can be found at any sewing store. It should be found on the same isle as the other elastic. It will look like this.
You will take the end of your elastic thread and wind it around your bobbin by hand. You will not want to wind it by machine, it will not work. You will want to wind it loosely but tightly. Tight enough that the are no loose pieces of elastic thread bunching up. Loose enough that you aren't stretching the elastic as you wind. Click here for a rocking song and a video I found on YouTube that may help.
Thread your machine with regular thread. Then place your wounded elastic thread bobbin in its case. Increase your stitch length to a 3.5 at least. Then sew.
It really doesn't matter how you do this. This is how I do it. I start a little away from my hem stitch line using it as my guide to sew along the edge of the sleeve.
When I reach my starting point I sew over the starting stitches by two or three. Then I lift my pressure foot and shift the sleeve over until the edge of my pressure foot is touching the line I just finished.
I continue going around the sleeve in this manner until I have completed three rows of stitching. When I finish my third row I back stitch and then lift my pressure foot and pull the sewn sleeve away from the threads. I make sure I leave some elastic thread. Don't clip your threads tight.
Then I tie my starting elastic thread and my ending elastic thread in a square knot. This will ensure you elastic thread will not come loose and start unwinding. This is what the under side of your shirt will look like.
This what the right side of your sleeve will look like.

Do this to both sleeves.