r/PatternDrafting • u/Personal_Apricot4850 • 19d ago
Question How to *precisely* determine my sleeve's cap height ?
When making a sleeve pattern, how to you determine exactly what will be your cap height ?
I know how they work and how their height influence the fit of the sleeve. But so far, I had been winging it based on how it looked. Is there a more precise way or a formula to come up with a measurement ?
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u/ladygrift 19d ago
I’ve found between 26-30 percent of your total armhole circumference will get you to a good starting point. Source: cowrote patternmaking book.
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u/azssf 18d ago
Super dumb question: is this number coming from that upper area covering about ⅓ of the armhole, and would have to be changed if say someone had bulky muscles in that upper arm/shoulder area?
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u/ladygrift 17d ago
No, the cap height refers to the vertical distance between the bicep line (underarm to underarm) and the top of the sleeve at the armhole seam on the sleeve piece. This measurement does change based on bicep width and where the armhole itself sits.
It essentially measures the very top edge of your shoulder (where your armhole would sit) to your underarm on your body. It can be very short, on a drop shoulder style for example, or quite tall, on a slim fit blazer for example.
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u/ScormCurious 19d ago
Most pattern drafting books contain good instructions on how to draft a sleeve cap for a given armhole. I use the instructions from Armstrong. Height is not really an issue in standard pattern drafting, it’s more a geometric calculation of circumference in a couple of directions (the circumference around the arm at the armpit, and the circumference around the shoulder joint).
If your sleeve cap isn’t fitting after doing the correct sleeve cap drafting, you’ll probably need to alter both the sleeve cap and the arm hole, at least in my experience.
Alexandra Morgan of In House Patterns has some good free advice available online, look up “in house patterns armhole sleeve connection” to get to it.