Mastering Circle Templates

Making the compass

Now let’s make our compass! Sure, you could dust off the ol’ compass from your school years, but I’ve personally found it more helpful to make your own. And, I’ve tried to make it easy with this free circle template compass download.

1. If using the template, you’ll want to either print it (be sure it prints at 100% scale! and use the 1" test square to double-check accurate sizing) on some very sturdy cardstock, or print it and glue/tape it to a piece of cardboard or other thicker material. Whatever material you use, you’ll want to make sure you are able to puncture a very small hole into it - e.g., cutting board plastic might not be the best for this use case, but cereal box cardboard works great (that’s what I’ve used).

Note that, depending on the size of your desired finished circle, you may not need the full length of the compass. Feel free to cut it down to about an inch beyond your desired finished circle radius. You’ll see that for my 7" diameter finished circle (i.e., 3½" radius), I’ve gone ahead and cut my compass just beyond the 4½" mark.

2. Use your stiletto, seam ripper, or other sharp point to poke a small hole at the 0" point where the perpendicular lines intersect toward the bottom of your compass. You want a hole just big enough to fit the lead of your pencil, and not so big that your pencil would wiggle around it in.

3. Now is where our calculations come in. We will now make similarly small holes where the vertical line intersects the tick marks at the radius measurements for our fill and background templates. For my example, I’d like my finished circle to have a 3½" radius. So, I will make a small hole at 3¾" (3½" + ¼" = 3¾") for my fill template, and a small hole at 3¼" (3½" - ¼" = 3¼") for my background template.

And that’s really it! Now you have your key tool for making your circle templates.

Making a hole at the 0" point of the compass

Our template is almost complete, but it’s really useful to have markings around each of your circle templates to duplicate onto your fabric pieces so that you know where fill & background curves should match up when sewing them together - otherwise, curves could be sewn unevenly, making for a wonky final result.

4. To make these marks, use the center point and your ruler to draw a line that divides your circle in half. Now, draw a line through the same center point that is perpendicular to the line you just drew.

5. Use the 45° line on your ruler to draw another line that is - you guessed it! - 45° from one of the lines you’ve just drawn, ensuring it also intersects with the center point. Then, draw another line perpendicular to this line.

6. Cut out your circle, and you have a completed fill template!

Repeat the steps above to make your background template, only instead, place your second pencil in the further in hole on your compass. Once you have both templates, it’s helpful to place the background template on top of your fill template to make sure that all your markings align.

Half circle templates + trimming

Thankfully, most of the steps for making half circle templates are the same as for full circle templates. The only difference is that, now we need to account for the straight edge seam allowance. With half circle templates, you have the option to add in some wiggle room for trimming your straight edge. I like to take advantage of this since sewing curves does sometimes cause us to stretch and warp our fabric a bit. And, who doesn’t want a less stressful sewing experience?

1. Make sure that your template material has a straight edge at least an inch longer than your desired finished circle diameter. Along this straight edge, use your ruler to measure and mark a line that is ½" inside this edge (if wanting room to trim) or ¼" inside this edge (if not wanting room to trim).

Here is where it will begin to feel like deja vu of full circle templates.

2. Use the bottom horizontal line at the 0" point of your compass to line up the 0" hole in the center of the line drawn. Now, place your pencil in the 0" hole, and turn it a bit to make a small mark on your paper so that you’ll have a center point for the half circle you’re about to draw.

3. Holding the pencil at 0" steady, place your other pencil in the further out hole on your compass (i.e., your fill template radius), and draw a half circle onto your template material, going all the way from edge of your template material to the other. Your circle will go past your straight line on both sides.

Now let’s make those marks!

4. Use the center point and your ruler to draw a line that divides your circle in half and is perpendicular to the straight line drawn.

5. Use the 45° line on your ruler to draw another line that is 45° degrees from one of the lines you’ve just drawn, ensuring it also intersects with the center point. Then, draw another line perpendicular to this line.

6. Cut out your circle, and you have a completed half circle fill template!

Repeat the steps above to make your background template, only instead, place your second pencil in the further in hole on your compass. Important! Whether you decided to draw your initial line ½" or ¼" inside your template’s straight edge (step 1), use that same measurement when drawing this line for your corresponding background template. Note also that if you opted to add room for trimming, you will want to cut a background piece of fabric that is at least ½" wider & longer than your desired unfinished half circle unit.

Once you have both templates, it’s helpful to place the background template on top of your fill template to make sure that all your markings align.

Trimming sewn half circles

If you opted to add some extra wiggle room into your template for trimming, you may be wondering how to trim up your half circle unit once it’s sewn. Essentially, since you’ve added an extra ¼" to the straight edge, that’s the edge we’ll be concerned with trimming. Of course, I always advocate for cutting out background pieces a bit larger than their unfinished size (maybe a full inch longer & wider) to allow for trimming all the way around once unit is all sewn.

1. Orient your unit so that the straight edge of your circle runs along the right side - or left side, if you’re left-handed.

2. Place your ruler on top of your unit so that the seam at the widest horizontal part of your circle runs through the point on your ruler that is your finished radius + ¼".

Continuing with my 3½" radius finished circle example, I would make sure that the seam tangentially hits the line that is 3¾" to the left of my ruler edge.

3. Using your ruler, make sure that the widest vertical part of your circle measures your desired finished diameter along the line that is ¼" in from the edge of your ruler.

Continuing with my 3½" radius finished circle example, I would make sure that the height of my circle measures 7" along the line that is ¼" in from the left edge of my ruler.

4. Once your ruler is placed on your unit meeting the criteria from 2 & 3 above, trim along the edge of your ruler.