This is so easy you are not going to believe it. I snooped around because I figured someone posted this somewhere already and I hate to be redundant if there is already good info out there. However, each tutorial I saw involved a lot of steps of cutting and pasting. These are far too many steps for this simple procedure!
But before I begin, I need to get something off my chest-there is no need to slice and dice a pattern to make adjustments. Seeing semi-kalediscopic, collaged pattern pieces with 3 kinds of tape and glue makes me feel a bit twitchy. Here's why: The slicing and slashing are a time consuming method to make changes that should actually be applied to the outer edges of the pattern.
Let me fill you in on an industry trademark- professional pattern makers rarely cut into their patterns. We work around the perimeter to maintain the integrity of the original (since we need to keep every iteration until fit is approved). Also, if done on the computer, it is almost mandatory to address changes this way. If you are making oak tag patterns that stuff is serious to cut and paste. You will need packing tape to put it back together. But really, the main reason the perimeter works best is because it is the quickest method once you know what to look for.
Why am I going way off topic with this? Because I want to show you how to do supposedly complex alterations in quicker and easier ways by working around the edges/perimeter. Ideally it's part of a bigger discussion if this makes sense to everyone.
So let's get back to one of the easiest- the shoulder width adjustment!
You know how the numbers work now from last weeks post and how to determine what you magical number your shoulder width should be. First thing is to determine how much you will need to add or subtract. It's really basic, but let me give you my formula that only looks complex:
Now we will put those numbers to use starting with increasing the shoulder:
To reduce the shoulder width you will do the opposite:
Make sure you add your seam allowance width back and then you are good to cut the new edge. That's it! I'm kinda biased since I do this all the time, but what about you- does this make sense? Hoping that it can help you out!