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When checking a component at the bench, the square you reach for affects both speed and confidence. A traditional try square is quick, stable, and excellent for checking a broad face or a long shoulder. A small combination square is more versatile: it can check 90° and 45°, measure short distances, and mark a line from an edge. Neither is automatically better. The right choice depends on the size of the work and whether you are checking, measuring, or marking.
What each square is for
A try square has a fixed blade set at 90° to a stock. The stock normally has a substantial body that sits against the edge of the component, while the blade reaches across the face. That fixed arrangement makes it fast to use. There is nothing to set, tighten, or accidentally move.
A combination square has a movable head that slides along a graduated rule. Most have a 90° face and a 45° face, along with a scriber or bubble level. The head can be locked at a chosen measurement, so the tool works as a square, depth gauge, marking gauge, and sometimes a basic centre finder.
For general carpentry, a 6-inch combination square is a useful size. A small 3- or 4-inch model is easier to use on narrow components, but its short rule gives less reach. Try squares are commonly sold with blades from about 3 to 12 inches. A 6-inch try square is a practical bench size; a 9- or 12-inch version is more useful on cabinet sides, wide rails, and larger joinery.
Checking 90-degree edges and shoulders
Use a try square when you want to check whether a cut edge is square to a face. Hold the stock firmly against the reference face and look for light between the blade and the cut edge. Check in more than one place if the edge is wide. A joint can be square at one end and out at the other because of a saw cut that wandered or a plane that was tilted.
The broad stock of a try square is usually more comfortable against a component than the narrow head of a small combination square. It is also harder to rock, particularly when checking a long edge. On a door rail, face frame member, or planed board, that stability saves time.
A small combination square is fine for short components, especially when the edge is only 25 to 75 mm wide. It becomes less convenient when the blade is too short to span the work or the head catches on clamps, arrises, or uneven surfaces. For checking the shoulder of a small mortise, tenon, drawer part, or shelf pin rail, its compact size can be an advantage.
Try square versus small combination square
| Feature | Try square | Small combination square |
|---|---|---|
| Best use | Fast 90° checking on bench components | Checking, measuring, marking, and 45° work |
| Typical useful size | 6 to 12-inch blade | 3 to 6-inch rule |
| Stability | Usually excellent because the stock is fixed and broad | Good, but depends on head fit and locking screw |
| Accuracy risks | Damaged blade, loose stock, or a worn reference face | Loose head, dirty rule, play in the slot, or a shifted setting |
| Other jobs | Mostly 90° checking | 45°, depth setting, short measurements, and marking |
| Typical cost trade-off | More tool for one main job | More functions, but cheap versions can be less precise |
Accuracy and failure modes
Before trusting either tool, test it. Put the stock against a straight reference edge and draw a line along the blade. Flip the square over, keeping the stock against the same edge, and draw a second line beside the first. If the lines diverge, the square is not true. The gap may be small, but a 0.5 mm error over a 100 mm check can create a visibly poor shoulder or cumulative error in a cabinet.
Try squares can go out of square if dropped, if the stock loosens, or if the blade is bent. Wooden-stock versions may also move with moisture, particularly if one face is unfinished or the joint between stock and blade has opened. A metal-stock square avoids some of those issues, but a cheap pressed or poorly machined stock can still be inaccurate.
Combination squares have a different weak point: the sliding head. Dirt or sawdust in the slot can make it bind or sit slightly crooked. A locking screw that feels tight may still leave the head with sideways play. Set the head, press it against a straight edge, and try to rock the rule. Any movement is a warning. The rule itself should also be straight and have clear graduations that do not begin several millimetres from the reference face unless that offset is intentional and easy to account for.
What to buy for bench work
If most of your work involves chisels, hand planes, saws, and fitting joints, a good fixed 6-inch try square is a sensible first purchase. Choose a blade that is straight, a stock with a broad reference face, and a clearly defined inside corner. Avoid a square with a sharp casting burr that prevents the stock sitting flat.
Choose a small combination square if you regularly mark short shoulders, check 45° cuts, set a line a fixed distance from an edge, or need one compact tool in a tool belt. A 4- or 6-inch rule covers many cabinet and trim tasks. Look for a head that locks without excessive force and a rule that does not twist in the head.
The cheaper option is fine when you are checking rough framing components, setting out non-critical cuts, or using the tool against a known straight reference. It is less acceptable for fine joinery, plane setup, or repeated marking where a small error is transferred to every part. In that case, spend more on one accurate square rather than buying several multifunction tools with loose heads.
Using either square correctly
Clean dust from the reference edge before checking. Hold the stock against the face without forcing it, and keep the blade or rule flat against the component. Check both ends of a long edge, then check the opposite face if the part will be used in a visible assembly. For marking, use a sharp pencil or knife and mark from the same reference face every time.
Keep the square in a tool belt or drawer where the blade cannot be bent. Do not use it as a pry bar or tap it against a chisel. A try square is the faster specialist; a small combination square is the better compact generalist. If your bench work is mostly 90° checking, buy the more stable tool. If you need measurement and 45° marking as well, accept the combination square’s extra adjustment and inspect its fit before relying on it.