Cutting straight lines in wood is one of those things that gets easier with practice but there are some hints and tips that can help you start off on the right foot.
Cutting with Power Tools
This article covers hand saws. You might think that it’s easier to cut straight lines using power tools like jigsaws or circular saws, particularly now that power tools are much more affordable. But jigsaws are very difficult to use on a straight line as they tend to wander about, particularly if the blade isn’t sharp.
Circular saws are better for straight lines, particularly if the piece can be positioned in such a way that the guide can be used for the whole length of the cut. But that’s often not possible, and for a beginner the noise and dust can be very off-putting, leading to mistakes.
Measuring and Drawing the Cut Line
The most important thing to do is spend time measuring your line and making sure that it’s straight. Measure, draw your line and then measure again. If you are cutting a plank of wood in half, for example, you can measure the beginning and the end of the cut from one end.
But you can’t guarantee that the end of the plank of wood has been cut straight and true either, so measure from the other end as well, and if the results differ then you know you that you’ll need to use another method to make sure that you are cutting across at ninety degrees to the front edge.
Using a Carpenter’s Square
This is where a carpenters’ square comes into play. This is usually a steel blade set at ninety degrees into a wooden or plastic handle. There are more complicated versions adjustable for other angles too. Set this against the piece of wood and use it to draw the line, or just the beginning of the line if the square isn’t long enough.
If you do then have to carry the line on with a ruler, try and overlap the first line as much as possible, which will make it easier to match the extended line up. Once your line is finished, measure it up once more to check then you are ready to start cutting. Make sure the piece of wood is securely supported and held with clamps, vices or whatever else you have to hand.
Starting the Saw Cut
Set the saw up on the waste line of the cut, so the line will be just visible next to the teeth of the saw. The first few cuts should all be one way, drawing the saw back toward you then lifting it up and forward to draw back again. Hold the saw at an angle of about forty-five degrees to the wood and don’t drag it, just pull it back and allow the weight of the saw to cut into the wood.
Once there is enough of a groove for the saw to get a good start you can start a proper two-way sawing action. Increase the angle of the saw and get right over the piece so that you are cutting at almost ninety degrees to the wood. This makes it easier to keep it on the line and to keep the cut upright as well. Stroke the saw through the wood, you are there to guide it, not push it through.
Developing a Saw Action
Use your shoulder as a fulcrum and move your wrist as you saw to keep the saw level through the stroke. If you lock your wrist the saw will go in a curve which makes it less accurate.
As you go, keep an eye on the line at all times. If you stray from it, pull back and start that section again. If you try and bend the cut back to the line then you’ll have a curve in the cut which will be difficult to sand or plane out.
Keeping the Saw on Track
As well as following the line accurately you will need to make sure that the cut itself is vertical. Getting over the work as much as possible will help with this. Allowing the saw to drop down to a shallower angle will make it harder to keep the cut vertical and harder to change direction if you veer away from the line.
As you get toward the end, make sure the piece of wood is still fully supported otherwise the waste bit will tear off and ruin the cut. Clamping a piece of waste wood to the end of the cut line, so that you cut into this as you finish, will preserve a clean cut on the piece itself.
Damage Limitation One final point to make about power tools versus hand sawing is that if you are a beginner, the damage you can do with a power saw until you are used to using it is a lot less than the damage you can do with a hand saw. So take it easy at first.