Buying Combination Squares & Double Squares
Combination Squares are a more modern style of metal square, and I find them very useful in my workshop, for many tasks. The bar of the square slides back and forth to give you different lengths for measuring and marking your boards. The bearing surface of the square allows you to scribe both a 90 degree line and a 45 degree line.
Double squares are like combination squares, but without the 45 degree bearing surface. The below pictured double square is of excellent quality, and you can find it here.
A combination square also works great as a depth gauge, for example, when you’re chopping a mortise.
It’s also useful for finding the center of boards. Just as a little side tip, to find a board’s center, I adjust the combination square close to what appears to be the center, and then I mark from both sides, and make marks with a pencil or a marking knife.
Right in-between those two marks is the center of the board.
Combination squares are also convenient because they’re usually purchased new, and are usually accurate if you buy them from a reputable maker. Vintage squares often need some work to get them back into square. I’ll talk about how to test a square for accuracy in just a minute. But I recommend that my students buy both a 6-inch combination square and a 12-inch combination square. I’ve found that those sizes cover most of the tasks that I encounter when building furniture.
My Favorite Combination Squares (Budget-Friendly)
I’m always on the lookout for affordable tools that are also accurate, and I’ve found a couple combination squares that meet those criteria. I’ve bought a bunch of these for my school, and I have yet to find one that’s “out of square”. This particular brand runs about $15 for the 6-inch combination square and about $17 for the 12-inch combination square. You can find the 6-inch combination square here on Amazon for about $14 (including shipping) and you can find the 12-inch combination square here on Amazon for about $17 (including shipping) . They don’t adjust as smoothly as the more expensive combination squares that I’ll mention below, but for the price, I can overlook the smooth adjustments. I have bought about 7 of them for my woodworking school, and they were all square.
My Favorite Combination Squares (If You’ve Got Extra Money to Spend)
If you’re not on a very tight budget I’d recommend buying a new Starrett 6-inch combination square (I like the version with the 4R markings). I found the best prices here on Amazon (under $75) and here on Highland Woodworking. And here is the 12-inch Starrett combination square.
If you can find a used Starrett combination square, in person, and can test it for accuracy (see above) then go for it! If you want to buy a used Starrett combination square on eBay, ask the eBay seller to show you pictures of them testing the square: test the squareness by lining the square along the edge of a board and scribing a line along the inner side of the blade. Flip the square over and try to draw a line over the same line, again with the inner side and outer side of the blade. If the lines line up, then it’s good! If not, then move on or negotiate a lower price.
UPDATE: I have recently gotten two other new 12-inch combination squares from Taylor Toolworks that I really like, this PEC 12-inch 4R Combination Square and also this LaSquare 12-inch 4R Combination Square. They are both quite well-made, beefy, and at about $75 each, they are more affordable than the Starrett 12-inch combination square. You can see Taylor Toolwork’s full line of combination squares here and their double squares here.
Quick Links to All of My Recommended Combination Squares
Here are quick links to the combination squares that I’ve recommended above, so you can quickly compare prices.