You may remember that I was working on a white blouse with black piping. It was temporarily abandoned to finish Alex's blouse. There is still some work to do on it, but in the meantime anonymous asked if I could clarify how I fit the sleeve. Sew the underarm, should have read baste 3" on either side of the underarm seam.
When I took the sleeve drafting class with Kenneth King we sewed up half of our blouse sloper and one sleeve with 1" sas in the armscye and sleeve cap. After sewing the underarm make sure that you clip into the sas on the sewn portion. The seam line is marked on both pieces and you fold the seam allowance back on the sleeve cap and pin in place matching your notch to the shoulder seam. On my own, I hung the sleeve on my dress form and then tried it on. I have a right shoulder that is about 1" further forward of the left one so my shoulder mark is forward of the original marking. Because the sleeve was fit to my blouse sloper made from the moulage I made in an earlier class, the shoulder seam placement was already correct, but my arm itself is forward of this. He didn't change the shoulder seam placement when we fit the sleeve.
I kept shifting the sleeve backward and forward until I got the sleeve to hang well with no twisting. Sometimes you'll need more height in the sleeve cap and the 1" seam gives you enough room to adjust it. Mark with pencil slashes(on muslin) so that the new placement is marked on both the sleeve cap and the armscye. The underarm seam will have to move as well so that the ease is evenly distributed. In my case I have to move the underam on the sleeve towards the back an inch. It won't match the side seam but it isn't seen. It's better to have a sleeve that hangs well than a matched underarm seam! Before I sew it I'll pin it and baste in place to double check the fit.
Because my arm is so far forward, my right sleeve has more room in the front of the sleeve and a flatter back curve than you get in a commercially drafted sleeve.
If you find that the sleeve still needs adjustment in the good stuff mark the new placement with a Frixion pen. Don't know what that is? It's a cool pen that disappears with heat, an iron, and will reappear if you put it in the freezer for a few minutes. It disappears permanently if you wash it in the invisible stage. Available in a variety of colors, but unfortunately not in white. It only works well on smooth fabric. I got a 3 pack at Staples, but Amazon has them in a nice assortment of colors.
By the way, this pj like top was the inspiration for my blouse.