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One of the most crucial steps when you have half square triangle units in a quilt block is trimming them down to the exact size the quilt pattern calls for. Whether you're making them 2, 4, 8, 16 (or even more) at a time, quilt pattern designers leave a little wiggle room to trim your HSTs for optimal accuracy.
As the saying goes, there's lots of ways to skin a cat. You don't need a specialty HST ruler to trim half square triangles, but, there are two on the market that I think are amazing! I tested both of them and there are pros and cons to both, so let's get into it!
Bloc Loc HST Rulers
Shop Here: Bloc Loc 2.5", 4.5", 6.5" set
The Bloc Loc Rulers are square, acrylic rulers with a grooved channel on one of the diagonals. After pressing your HST's seam to the side, the channel allows you to "lock" the ruler onto your seam, which keeps everything lined up while you trim all 4 sides. I love to use my Bloc Loc Rulers in conjunction with my rotating cutting mat, so I can turn the mat and get a comfortable angle as I trim each side.
Pros:
- Grooved Design: The ruler has a groove that locks onto the seam of the HST, making trimming very accurate and preventing slippage. Additionally, there are non-slip pads on the base of the ruler that provide grip.
- Consistent Results: Because there's no measuring needed, just locking into the groove, you get precise, clean cuts every time, which is great for maintaining accuracy across multiple HSTs.
- Quick to Use: The locking feature allows for fast trimming once you align the groove.
- Great if you prefer pressing seams to the side.
Cons:
- Price: Bloc Loc rulers tend to be more expensive than standard rulers or trimmers.
- Single Purpose: The ruler is only useful for HSTs and isn't as versatile for other quilting tasks.
- Need Multiple Sizes: If you're making different sizes of HSTs, you’ll need multiple Bloc Loc rulers for optimal accuracy and if you have irregular sizes of HSTs, they're not as easy to use.
Clearly Perfect Slotted Trimmers
Shop Here: Clearly Perfect Slotted Trimmers
The thing that sets the Clearly Slotted rulers apart is that you trim before pressing. So, while your HST is still right sides together, you align the seam line with the seam line marking on the ruler and trim two sides at a time, which in theory should be faster because you're trimming 2 sides instead of 4 as with Bloc Loc. However, the Clearly Slotted Ruler also has little channels that allow you to trim off the dog ears, so that's two more cuts...so it really is 4 cuts total still and I don't find it to be faster for me than Bloc Loc. I find the channels to be a little tricky and I nick my rotary blade on the acrylic quite often--we all know what a horrible feeling that is!
Pros:
- Multi-Purpose: You can trim various sizes of HSTs with just one tool, making it more versatile. Between the 2 rulers included in the pack I linked above, you can trim 11 different sizes of HSTs.
- Slotted Design: The slots allow for trimming dog ears at the same time you square up.
- Budget-Friendly: Typically more affordable than Bloc Loc rulers, especially if you need to trim many different sizes of HSTs.
- No Need to Press First: You can trim the HSTs while they are still folded, eliminating an extra step.
- Great if you prefer pressing seams open.
Cons:
- No Seam-Locking Feature or non-slip pads: Without the seam-locking groove, there’s more potential for slight movement while trimming.
- Constant Nicking of your Rotary Blade: The channels for trimming the dog ears are great in theory, but I found them awkward to cut into and I ended up crashing into the acrylic quite often with my rotary blade.
Square Quilting Ruler:
Again, you don't need to invest in specialty HST rulers. It's very easy to trim HSTs with your normal quilting ruler. I have a 6.5" and a 12.5" ruler and they are both fantastic for trimming HSTs. I like to use washi tape to mark where I need to line up my HST and use my rotating cutting mat. I press my HST first, then trim simply because I don't like to trim dog ears but, you can trim first, then press and trim dog ears if you don't want to have to lift your ruler.
Pros:
- You probably already have one: If you're on a budget or space is at a premium in your sewing space, use what you've got!
- It's versatile: One trick ponies are kind of silly if you're not going to be making lots and lots of HST quilts. You will use your square rulers for all sorts of things!
- You can trim any size of HST: No size limitations, so make all the funky sizes your heart desires!
Cons:
- Less efficient: It's definitely more fussy to get things lined up and if you press first, you'll have to lift your ruler and line up again. Washi tape marking help with lining up efficiently, but the other options are much easier to use.
- More room for error: I find I'm not as precise with my square rulers as I am with the other tools.
Overall Comparison:
- Bloc Loc HST Rulers are perfect for quilters who value precision and are willing to invest in a premium tool for consistent results, especially for those making HSTs frequently. I would recommend for quilters who prefer pressing to the side.
- Clearly Perfect Slotted Trimmers are great for quilters looking for versatility and efficiency, especially if they are trimming a wide range of HST sizes or want to save time by trimming dog ears in one step. I would recommend for quilters who prefer pressing open (you can definitely press to the side, too!).
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Square Quilting Rulers are great for the budget or space conscious quilter. They are more versatile, but less efficient and can be a bit fussy to use. I recommend marking measurements with Washi tape to make lining up a quicker process.