How to Use the Clearly Perfect Slotted Trimmers

Published July 2026

Join Jen for a look at the Clearly Perfect Slotted Trimmers, a set of two acrylic trimmers that make half square triangles without drawing a single line. This tutorial covers how to read the trimmers, how to build a strip unit, and how the slots trim your dog ears while you cut.

In this video, you'll learn:

• How the A and B trimmers cover finished sizes from 1" to 6".
• How to build a strip unit and sew it on both edges.
• How to place the dashed line on your stitching to cut a perfect unit.
• Which slots trim the dog ears, and which ones to leave alone.
• How to work back across the strip so very little fabric goes to waste.

Check the links for everything you need.

Introduction

Half square triangles turn up in quilts everywhere, and plenty of quilters would happily skip the part where you draw a diagonal line and then track a quarter inch on either side of it.

The Clearly Perfect Slotted Trimmers take a different route. There's no line to draw, and the dog ears come off as part of the same cut. Two trimmers arrive in one pack, and between them they cover half square triangles from 1" finished all the way up to 6" finished.

These come to us from New Leaf, designed by Kari Carr. They reached out to introduce the product, and it turned out to be a genuinely clever piece of design from a family run business. It's a real solution to something quilters have been doing the long way for years.

What You'll Need

• Clearly Perfect Slotted Trimmers. Both the A and the B trimmer come in the one pack.
• Rotary cutter with a fresh, clean blade. These cuts need to be clean every time.
• Spinning mat. It makes a real difference to both accuracy and safe cutting.
• Iron and pressing surface
• Presser bar and clapper, for opening seams flat
• Gypsy Quilter grippy dots, an optional addition so the trimmer doesn't shift
• Two contrasting fabrics

Reading the Two Trimmers

Each trimmer is marked with unfinished sizes, and each one gives you six options.

Trimmer A starts at 1.5", which finishes at 1", then 2.5" finishing at 2", and continues up to 6.5" finishing at 6".

Trimmer B works the same way at the half sizes. It starts at 2" finishing at 1.5", then 3" finishing at 2.5", up to 6" finishing at 5.5".

The slits cut into the corners are the clever part. Those slots are what remove your dog ears, so trimming and tidying happen in the same pass. Two larger trimming units are also available if your project calls for something bigger than this set covers.

Building Your Strip Unit

Every cut you're about to make runs on an angle, which means bias, so a little care at the start pays off through the whole project.

1. Press each of your fabrics well.
2. Lay them together and press them as a pair, so the two layers have good contact.
3. Cut your strips with both fabrics together. They're married from the very beginning that way, and the edges match exactly.
4. Sew a .25" seam along both long edges.

Sewing both sides produces something closer to a tube than a normal strip set, which takes a moment to get used to. It's also what lets you work back and forth across the strip and get a great deal out of it.

Strips cut to 21" are a comfortable working length. That's half the width of fabric, and it's the measurement our free download is built around. If you'd rather work from leftovers, that works just as well. Put two fabrics together, sew both edges, and the trimmer does the rest.

Cutting Your Half Square Triangles

Decide on your finished size and find it on the trimmer. For a 4" finished unit, that's the 4.5" line on trimmer A.

1. Look just beneath your size for the dashed line. Lay that dashed line exactly on your stitching. That's precisely what it's there for.
2. Apply pressure to hold the trimmer steady and cut across.
3. Rotate your mat rather than repositioning your body, and cut the second side.
4. Now cut through the slots to remove the dog ears.

Only two of the slots are the right ones. There are slots all along the trimmer, and the pair you want are the two closest to the bottom, nearest your stitching. Those are the ones that take the dog ears off. Cutting the others won't give you what you're after.

Pressing Your Units

Open the unit and press. You have two good options, and the project decides which one you want.

• Press the seam open for a project where everything should lie as flat as possible. A presser bar over the top helps open it up, and a clapper on top holds it flat while it cools.
• Press to the dark if you're building pinwheels or anything else where you want interlocking seams.

Then look at your unit. No dog ears to trim off, because that already happened.

Working Back Across the Strip

This is why you sewed both edges.

1. Turn the trimmer around to the second stitching line.
2. Set the dashed line on that stitching, and use the edge you just cut rather than starting fresh. Scoot the trimmer right along it.
3. Cut, then take the two correct slots again.

Keep alternating down the strip. Rotate the mat to whatever vantage point suits you, and very little fabric goes unused.

A pair of grippy dots is worth considering. The corners of the trimmer are the parts you're least likely to have a hand on, so a grippy dot in each of those corners keeps everything from shifting mid cut.

The Free Download

A simple pattern is available as a free download so you have somewhere to put all these units. It offers two layouts, a straight set and a chevron, and it's an afternoon of sewing rather than a long project.

The table topper shown uses 4" finished blocks in an eight by eight layout. Eight blocks at 4" gives 32", so with the raw edge accounted for before binding, the finished topper is 32.5" square.

Page two of the download covers the other sizes. Choosing 3.5", finishing at 3", would give you a 24.5" square instead. It also lists what to cut your strips to, how many half square triangles come out of each strip set, and how many binding strips you'll need.

If a tool makes the work more accurate, faster, and more fun all at once, that's an easy yes. Whether you need half square triangles for a project already underway or you'd like to try one of the layouts in the download, these trimmers change the job entirely!