1.11 Checking the accuracy of a Try-Square

Place the try-square flush against an object’s straight edge (e.g. a piece of wood) and draw a perpendicular line. Flip the try-square horizontally and check if the same edge aligns with the drawn line. The try-square is accurate if both edges of the ruler are squared to the drawn line.

1.12 Measuring & Marking

If your try-square is properly square (see 1.11), you can use it to check for right angles such as on a workpiece or a right-angled joint.  

The try-square can also  be used as a ruler to make measurements and markings.

1.21 How to measure

The first measurement is determined by where the 0-point on the vernier scale crosses the main. In the example below/on the right, it is 45mm.

Secondly, read the measurement on the vernier scale that aligns with the main. As shown, it is 0.5mm.

Therefore bringing it to the final measurement of 45 mm + 0.5 mm =  45.5mm.

The reading will be based on the vernier scale that aligns with the main, (0.1mm).

If the 0-point is found left to the main scale, there is a negative zero error. Conversely, if the 0-point is found right to the main scale, there is a positive zero error.

Negative zero error – Obtained reading is smaller than correct reading.

Positive zero error – Obtained reading is bigger than correct reading.

Correct reading = Obtained reading – Zero Error

1. Mark the desired cut on at least 2 sides of a workpiece if you are making a rough cut (e.g. cross-cut to divide a plank in two). Mark all 4 sides of the workpiece for more precision (such as in the case of a joint) as this will also guide the chisel-work afterwards. You can use a square to draw these lines.

2. When using a push saw (refer to the above/left image), position your workpiece in front of the holdfast so that it will prevent the workpiece from moving with the forward motion of the saw. Conversely, position the workpiece behind the holdfast when using a pull saw.

3. Align the saw outside of your drawn line. 

4. To steady the saw, anchor your knuckle against the side of the blade. This will keep the blade aligned with your drawn line and at a constant angle.

1.41 Using a Chisel with a Mallet

With a hammer or mallet, you can drive a chisel into wood. This can be used to set down a knife line, or to chop out large amounts of waste material.

Knife lines are shallow cuts that sever wood fibers and act as a stop cut to prevent tear-outs. They are usually used to outline a joint (e.g. a mortise or the shoulders of a tenon). 

How to make a knife line: Align the cutting edge of the chisel on your marking line, with the bevel facing towards the waste. Holding the chisel perpendicular, tap lightly with a mallet or hammer.

Chopping is a method to quickly remove large amounts of waste material using the chisel. 

How to chop: Hold the chisel upright with the bevel side of the chisel facing towards the waste, place the cutting edge of the chisel on the inside of the knife line before chopping to prevent cutting over the knife line. By applying more force with a mallet or hammer, you can sever more fibers thus removing more material. The angle of your chisel can vary depending on the amount of material you are trying to chop out. As this is an aggressive cut, it can cause tear-outs or cracking in the material.