10 Best Combination Squares of 2021 – Reviews & Top Picks
Whether you need to measure an angle, mark a miter, or see if a piece of material is straight or square, a combination square can give you the measurements you need. They can provide perfect 45 and 90-degree angles and allow you to check for squareness.
You’ll find these little tools to be invaluable for woodworking, metalworking, and stonemasonry too. They’re pretty cheap to get started with, though the premium ones can still cost a pretty penny.
Since choosing one out of the many available can be a difficult task, we decided to make it easier by writing up 10 reviews that compare some of the most popular combination squares on the market. Hopefully, this will save you the hassle of trying them out for yourself just to build several out-of-square projects along the way because of their inaccuracies!
A Quick Comparison of Our Favorites
|Best Overall||Irwin Tools 1794469 Combination Square||
|Best Value||Mr. Pen-Combination Square||
|Premium Choice||Starrett 10H-6-4R Cast Iron Square||
|Swanson Tool TC132 12-Inch Combo Square||
|Johnson Level & Tool 400EM-S Metal Combination Square||
The 10 Best Combination Squares – Reviews 2021
1. Irwin Tools Combination Square – Best Overall
Irwin is a trusted manufacturer of tools, so we knew their combination square was going to be one of our favorites. This one has all the features we’re looking for in a durable package that’s priced reasonably. For us, that covers all the bases.
The Irwin combination square has a built-in bubble level for when you need to check your level at a glance. It’s got a rust-proof blade with precision-etched graduations that are also painted black to make them easy to read so you can always get your measurements quickly.
This square’s head is made from cast zinc. It slides smoothly, but if you take it off completely, it’s a bit of a pain to get back on. Still, this was the square that represented the best overall combination of price, value, and performance, which is why it tops our list.
2. Mr. Pen-Combination Square – Best Value
Sometimes, you just want the cheapest tool that can do the job correctly. If that sums up your search for a combination square, then the Mr. Pen combination square is probably perfect for you. It’s dirt-cheap but fully functional, which is why we think it’s one of the best combination squares for the money.
This square is 12 inches long and has markings that go down to 1/32 inches. It features a stainless-steel blade that’s completely rust-proof and easy to read. There are even a built-in bubble level and a brass scriber helping to expand this tool’s usefulness.
To be honest, this tool probably won’t hold up to daily use. But it will definitely help hobbyists and non-professionals get square and accurate markings and measurements on many projects. Overall, we feel confident recommending the Mr. Pen combination square for its great value.
3. Starrett Cast Iron Square – Premium Choice
Starrett is known for making tools of an uncompromising quality, and you can feel it the moment you hold the 10H-6-4R Cast Iron Square. It’s very solid, and the extra weight gives it a feeling of quality.
One of the biggest draws to this square is its accuracy. According to our measurements, ours was 100% perfectly in square, which wasn’t the case with most of the other squares we tested. And you can tell that this square is going to remain accurate for the foreseeable future. It also marks smaller increments than competitors; all the way down to 1/64 inches.
This square features a reversible lock bolt that allows you to flip and turn the ruler so that all four marked edges are perfectly usable. The head slides smoothly and is made from cast-iron to ensure it will last a lifetime. Of course, this level of quality and all these features don’t come cheap. But if you want the best and you’re willing to pay for it, the quality of this Starrett square is practically unmatched.
4. Swanson Tool 12-Inch Combo Square
This combination square from Swanson Tool is more than just an affordable but basic square. It’s also got an impact-resistant level bubble in the head with a built-in brass scriber for making marks when your pencil is nowhere to be found.
The head on this tool is made from die-cast zinc, ensuring it’s tough enough for the workplace. It’s got a spring-loaded bolt to keep the blade in place so the angle doesn’t change and it remains accurate. That would be great if it came perfectly square from the factory! It didn’t, but it wasn’t too far off, so we were able to fix it pretty easily.
Even once we got it perfectly square, we had another issue with the head. If you tighten it down to close to the end, you’ll get a lot of wobble in the ruler. We weren’t able to find a fix for this. The markings are also pretty difficult to read, but this is still one of the most durable and best functioning combination squares we tested, especially when you consider the reasonable price.
5. Johnson Level & Tool Metal Combination Square
We love a good deal, so cheap tools that function well always get a second look from us. This combination square from Johnson Level & Tool is one of the cheapest ones we tested, but it’s still a decent tool. It’s got a zinc head with a chip-resistant coating that feels like it’s going to hold up. To that end, it’s warrantied for a year, so we have some faith in it.
But there were still several flaws holding this tool back. For instance, the edges are surprisingly sharp, and several of our testers accidentally scratched themselves when they weren’t paying enough attention.
We also discovered that the locking mechanism doesn’t get quite tight enough. When you try to wrench it down, it pulls the head out of square. But if you’re gentle with it and you don’t overtighten the lock screw, it’s still pretty usable.
6. Stanley Contractor Grade Combination Square
If you need to mark something a bit larger than a standard piece of lumber, the Stanley Contractor Grade Combination Square is 16 inches long, providing plenty of room for marking oversized wood. It’s even backed by Stanley’s lifetime warranty, which does instill a lot of faith in this product.
Unfortunately, we noticed some problems with this square right away. First off, it’s not square! It wasn’t too far out, but it was enough to cause some frustration. After fixing it, we noticed how difficult the markings are to read. They’re etched, but we kept trying to shift our viewing angle to get the right amount of light to really make them out.
Like several other squares we tested, this one has rather sharp edges. You’ll probably want to file them down a bit to avoid scratching yourself.
7. WORKPRO Speed Square and Combination Square
At first glance, we thought the WORKPRO combination square looked like a quality tool. It also comes with a carpenter square; a nice extra that we certainly weren’t complaining about. But there were some flaws in execution that prevented us from really enjoying this square.
First of all, we liked the built-in level and removable brass scriber. The ruler feels solid and it has markings down to 1/32 inches that are easy to make out. However, they can be a bit difficult to read due to a lack of differentiating marks at sensible places like ½-inch or ¼-inch.
This square was more expensive than many of the others we tested. Unfortunately, it wasn’t 100% square, which meant we had to invest some extra time into it before it was usable. For the price, we were hoping for better.
8. Empire Level Professional Combination Square
This professional combination square from Empire Level is 16 inches long for when you’re marking more than just 2x4s. But it’s not just bigger than competitors, it’s also more expensive than most. Since you can get cheaper products, we were hoping to see superior quality from this square, but that’s not what we got.
The head on this square doesn’t slide smoothly. Even with the set screw very loose, it only moves in short bursts. And no matter where you set it, it’s not quite square. We were able to fix it since it wasn’t far off, but we shouldn’t have to put that kind of effort into a brand-new tool. The final straw was a lack of metric graduations. Not everyone needs those, but if you do, you’ll be disappointed when they’re missing.
9. Kapro 325M Magnetic Lock Combination Square
The Kapro 325M Magnetic Lock Combination Square is an interesting concept with poor execution. Rather than the standard set screw that you loosen to allow the head to move, this square uses rare earth magnets to hold the head in place, allowing for improved accuracy. Unfortunately, ours wasn’t square from the factory and we couldn’t get it completely square, even with some filing.
We did like how quickly you could adjust this square thanks to the magnets. But for the extra cost, we’d rather stick to something that’s actually square. One final gripe; this square is supposed to include a belt holder but ours was missing!
10. Bahco Combination Square
Often, you get what you pay for. That’s not the case with this Bahco combination square. It’s more expensive than many competitors, but we think it’s lower quality. Our favorite things about it were the built-in level bubble and scriber. Outside of that, there wasn’t much to praise.
The ruler is marked in both metric and imperial. However, the metric markings are unusable. There’s no way to turn the ruler so that the metric side is facing correctly. The measurements are also half a millimeter off at the end, so any accuracy as a depth gauge is null and void.
Furthermore, the set screw has too much play. Even when snug, it allows a little movement. This just exacerbates the square’s biggest problem; it’s not square. For us, all these problems mean that this square just isn’t a great choice.
As you can clearly see, there are plenty of viable combination squares available. But there’s something that you’ll find in common amongst all of these tools; they all need to be checked for accuracy.
Is it Square?
You’re using this square to make sure that your measurements and cuts are precise, square, and straight. If your square is off, it can throw your whole project off.
The question is, how do you check if a combination is square is actually square?
Luckily, it’s not as difficult as you might think. And it’s so important that it’s worth repeating every time you start a new project.
How to Check if a Square is Square
To check your square, you’re going to need a flat piece of material with a straight edge that you’re certain is straight. You can use the factory edge of a piece of wood, tile, or something similar. This straight edge will be used for measuring the angle of your square. If the edge you use isn’t straight though, you’ll throw your measurements off.
Tighten the set screw on your square so it’s snug. Set a piece of paper on the material you’re using with one edge even with the straight edge. Place your square so that the 90-degree edge of the head is flat against the straight edge you’re using for measuring and the ruler is perpendicular to the straight edge. Trace a line down the ruler.
Now flip your square over and set it so that your ruler is in the same place you started the last line, but with the head facing the other direction. Trace another line.
If your square is in square, the lines will be directly on top of each other. But if your lines diverge, then the distance between them at the end is how far your square is out of square.
How to Fix a Combination Square That’s Not Square
Unfortunately, we noticed that many of the squares we tested were not completely square from the factory. This can be an extremely frustrating issue that prevents you from getting accurate marks and measurements.
Luckily, there’s a simple way to fix most of these squares. Often, the issue is that the groove within which the ruler sits is uneven. This causes one side of the ruler to sit higher than the other, changing the angle slightly so it doesn’t sit at a true 90 degrees.
You can easily remedy this with a piece of sandpaper. All you have to do is carefully determine which side is higher. Then, you lightly sand that side of the head to even it out. Once you sand it, you’ll want to repeat the test from earlier to make sure that you’ve got it completely square.
Other squares we’ve reviewed:
- Which square is best-suited for woodworking? See the answer here
- Which is our favorite speed-square? See our top 5 picks here
You might not think of a combination square as the tool that can make or break your project, but if enough of your edges are misaligned or out of square, the entire project could turn out poorly. That’s why we put so much time and energy into these reviews; we want your projects to turn out the way you intend.
For us, the square we’re most likely to trust in our projects is the Irwin Tools Combination Square. It’s got easy to read etched markings that are painted black, a rust-proof blade, and a built-in level and etcher just to expand this square’s usefulness.
We think that the Mr. Pen Combination Square represents the best value. It’s dirt-cheap, accurate, easy to read, and rust-proof. What more can you ask for?
For professionals, a different level of quality is required, which is why our premium choice recommendation is the Starrett 10H-6-4R Cast Iron Combination Square. It’s the most accurate out of all the squares we tested and features graduated markings down to 1/64 inches. Plus, the cast-iron head makes it durable, so you can trust that it’ll be around to keep all your future projects square and straight.
Featured Image Credit: Amazon
- A Quick Comparison of Our Favorites
- The 10 Best Combination Squares – Reviews 2021
- 1. Irwin Tools Combination Square – Best Overall
- 2. Mr. Pen-Combination Square – Best Value
- 3. Starrett Cast Iron Square – Premium Choice
- 4. Swanson Tool 12-Inch Combo Square
- 5. Johnson Level & Tool Metal Combination Square
- 6. Stanley Contractor Grade Combination Square
- 7. WORKPRO Speed Square and Combination Square
- 8. Empire Level Professional Combination Square
- 9. Kapro 325M Magnetic Lock Combination Square
- 10. Bahco Combination Square
- Buyer’s Guide