When I taught shirt-making I was often asked how to change the neck size of a pattern – usually how to increase the size. We are so used to simply adding on to a pattern in order to grade it up yet that is exactly the opposite of what must be done to increase the neck size. If you were to simply add on to the neck edge it would become smaller as you can see from the pattern here. In order to increase the neck size you must make the opening larger by removing material. Little or nothing is removed at the back neck edge as neck size does not increase in that area. Of course, the easiest thing to do is buy a pattern that has cutting lines for various neck sizes like Kwik-Sew 2777 that is shown here. However, that doesn’t always fit in with our plans, does it? If you make a lot of shirts you can cheat a bit by making templates from a pattern such as this. It works and it’s easy to do.
Once you’ve made the neck opening larger you will need to increase the length of the stand and collar. I like to walk the neck edge along the stand to see how much extra length I’ll need. On my son’s shirt I needed an extra 2″ so I slashed the stand in four places and added 1/2″ at each slash. I knew I’d need 2″ in the collar as well but I walked the collar along the stand just to be sure. A typical shirt collar runs from center front to center front but you’ll want to check your pattern in case it’s different from the norm.