Sleeve cap ease
The geometry is simple. Imagine that the boxes in the diagram at left are a small check pattern in a woven fabric. The sloped sleeve cap seam line within one rectangle in this checked pattern (line A) is slightly longer than the more vertical line of the armscye seam line in the same sized rectangle (line B) even though they both cover the same vertical distance.
The sleeve cap seam line must be made shorter (eased) so that the horizontal lines in the check can match in the finished garment. If there was no ease at all, the stripes would not match because the distances between them along the seam lines in the two differently-shaped pieces are different!
(Sorry for the klutzy diagram; someone equipped this struggling neophyte with a vector drawing app.)
The proof of my theory is that I can ease a sleeve into an armscye and yet match the horizontal stripes perfectly (or as close to perfectly as matters based on the six foot rule).
True enough, you don't need a lot of ease. But you have to have some to match horizontal lines in a checked woven between the garment body and sleeve cap. Happily, Burda 7576 seems to have just the right amount of sleeve cap ease.
The sleeve cap seam line must be made shorter (eased) so that the horizontal lines in the check can match in the finished garment. If there was no ease at all, the stripes would not match because the distances between them along the seam lines in the two differently-shaped pieces are different!
(Sorry for the klutzy diagram; someone equipped this struggling neophyte with a vector drawing app.)
The proof of my theory is that I can ease a sleeve into an armscye and yet match the horizontal stripes perfectly (or as close to perfectly as matters based on the six foot rule).
True enough, you don't need a lot of ease. But you have to have some to match horizontal lines in a checked woven between the garment body and sleeve cap. Happily, Burda 7576 seems to have just the right amount of sleeve cap ease.
I basted the sleeves of my muslin on the jacket body and then marked them up to assist in placing the pattern piece on my fabric, in much the same way I did in this post.
Once cut out of the fashion fabric, the sleeve cap is supported with a lightweight fusible interfacing, and eased using a bias-cut strip of wool.
The verdict? The horizontal matching is pretty good, but I still haven't figured out the vertical. Close though...
Once cut out of the fashion fabric, the sleeve cap is supported with a lightweight fusible interfacing, and eased using a bias-cut strip of wool.
The verdict? The horizontal matching is pretty good, but I still haven't figured out the vertical. Close though...
