Project 002 — How to Draft a Rounded Crown Sunhat

Today, I'll show how to draft a sunhat sewing pattern.

Hello my sewing mathy friends! Today, we're drafting a rounded crown sunhat. There are only two pattern pieces today, a petal shaped pattern piece for the crown and a brim that is made using the same method as the brim for the Bucket Hat. I think this is a really fun pattern to draft and the crown is really different than what we’ve explored so far in this series. Let’s get started!

If you missed the previous posts in this series, check them out here.

The rounded crown is made using SIX petal shaped crown pieces. The brim is dramatic and has a flatter angle than last week’s bucket hat. See the image above for an example of how the pattern pieces would look.

Today's lesson

Part 1: Collect information (Write down all the measurements, ease, seam allowance, etc.)

Part 2: Draft the Crown

Part 3: Draft the Brim

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Part 1 Collect Information

To make your own custom fit hat, you’ll want to gather a few measurements. Read this post for more info on measuring yourself for a hat. I’ve assigned a representative letter to each number we’ll need. I’ll use these letters to write the drafting formulas. When drafting your hat, replace the letters with your own numbers.

A Head circumference

B Ease at crown This is personal choice. I recommend measuring the inside of a hat that you like the fit of and then subtract your head circumference to find the ease you like.

C Seam allowance Designer’s choice

D Ear to Ear Read this post for more info on measuring this.

E Ease Ear to Ear This is personal choice. I’d aim for .5” to 1”.

F Brim radius This is how far the finished brim will stick out from the head. For a sunhat, I’d use around 3.5 to 5 inches. Or even larger for a very dramatic style.

Part 2 Draft the Crown

The origin of our petal shape pattern piece is a circle. Pretty cool right? Each petal is made from a 60 degree wedge. The diameter of the circle equals D Ear to Ear plus E Ear to Ear Ease. And the outer edge of the pattern piece equals 1/6 of the Finished Head Circumference A+B. You can draft this pattern piece by starting with a circle if you wish. I’m going to show you a different way that doesn’t require drawing a full circle. Both methods work.

For this approach, we’ll draft half of the petal shape and then reflect it and add seam allowance.

Step 1: Draw a line with length (D + E)/2. This line represents half the finished measurement from the middle of the head to the edge of the crown or the ear and is the center of the petal shape.

Step 2: Draw a second line 30 degrees to the right of the Line 1. (The full petal pattern piece will be a 60 degree wedge but for now we’re just drawing half of it.) Draw this line longer than needed. We’ll remove the excess later.

Step 3: Draw a line from the of Line 1 that is (A + B)/12 long and curves slightly up to the right. Where this line meets Line 1 should be a right angle so that it’s a smooth curve when we reflect the pattern piece. The curve can be very slight.

Step 4: Draw a line up from the right end of Line 3 until it meets Line 2.

Step 5: Clean up the pattern piece. Remove the excess section of Line 2, to the right of Line 4. Smooth out the junction of Lines 2 and 4 by drawing a curve inside the corner. Cut along the new curve to remove the point.

Step 6: Reflect the pattern piece across Line 1.

Step 7: Add Seam Allowance C to all outside edges. Draw a grainline parallel to Line 1.

As always, I recommend making a muslin. You may want to adjust the ease or the curve of the petal shape.

Part 3 Draft the Brim

By now, I think we can agree that drafting a brim is old hat (couldn’t resist ;). The approach is very similar to last week. We’ll start with a rectangle and slash and spread. For my sunhat, I want to increase the amount of spread so that the angle of the sunhat is less steep and flatter. I did a few experiments and decided that I really like the look of rotating the rectangles 22 to 23 degrees. You can start there and adjust for your personal preference.

Step 1: To draft the brim, we will first draw a rectangle that has a width of (A+B)/2 and a length of F Brim Radius.

Step 2: Next, divide the rectangle widthwise into eighths. If you’re using paper, you can do this by folding the paper in half three times. Cut the pattern along each fold stopping short of the pattern edge.

Step 3: Tape the left most rectangle to another piece of paper. Rotate each rectangle piece about 22 to 23 degrees. Repeat for each rectangle piece. The space at the bottom of the rectangles should be about 1.5” to 2”. (More on this next week.)

When spreading the rectangles, I was looking to create a shape that was almost a half circle. If I ended up with a half circle, I’d have a flat brim like in lesson one which was not the look I wanted. In my tests, rotating 30 degrees created bigger than a half circle and rotating 25 degrees was very nearly a half circle. So, rotating 22-23 seems to be a sweet spot for making this semi-circle shape.

Step 4: Trace the outer edge, drawing a smooth curve and connecting the gaps in the rectangles.

Step 5: Add the Seam Allowance C to the outer edge.

I recommend testing out your pattern using paper to get a sense of the shape and if you like it. You may want to adjust how much you rotate the pieces of the brim to create a bigger or smaller angle.

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I hope you enjoyed this post! Next week, I’ll share my in-depth look at drafting the brim using an angle of rotation versus an interval of space. I’m pretty excited about it and we get to use trigonometry. So, dust off your scientific calculators and get ready!

Please let me know in the comments if you have any questions. I do my best to make everything as simple and clear as possible but I’m sure I’ve missed things here and there.

Happy mathing!

Beth

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