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Using Backsaws for Accurate Sawing
By Samuel Colchamiro
New Jersey

Click on any picture to see a larger version.

In the modern world of precise woodworking machines, handsaws are often discarded as obsolete and inaccurate. Many woodworkers are drawn to the precision of the table saw and consider the classic handsaw far less essential. Woodworkers buy dado blades, crosscut blades, rip blades, and all kinds of jigs and fixtures for their table saw. They switch blades consistently for the most effective cut without realizing that if you learn to track a line with a standard backsaw, the world of woodworking is no longer limited to the accessories of your power tools.

Parts of the Saw

What is a Backsaw?

Backsaws are amongst the most accurate saws that you can have in your shop. A backsaw takes its name from the fact that a stiff spine is affixed to the back of the cutting blade. This allows the manufacturer to create a very thin blade that is still extremely stiff and only minimally flexible. This means that when making a precise cut for a dovetail or other piece of joinery, the saw will track a straight line without the user having to steer the saw and without too much effort. Most makers sell variations on three primary backsaws, the dovetail saw, the carcass saw and the tenon saw, each differing based on their depth of cut, aggression of cut, and tooth geometry. I will be discussing the dovetail saw, though everything is applicable to all saw sizes.

Backsaws typically have very fine tooth patterns. My Lie-Nielsen Dovetail Saw has 15 teeth per inch. The reason for the fine tooth pattern is that the fewer teeth per inch, the smoother the end surface will be. On joinery, like dovetails and tenons, the cut surfaces are often exposed and have very little blowout and saw marks on the surface, which allows the joint to come together straight off the saw. The more teeth, however, the slower the saw will cut. Machinists realized that to balance the many teeth, they needed to make the saw blade thinner. Thinner saw plates remove less material which allows the saw to cut a very fine line. To keep the blade from flexing, they affixed a brass or steel back on the saw. This stiffens the blade and holds it rigid, allowing accurate cuts to be made consistently.

Reading the Plate

Reading the plate of your dovetail saw will show how your tool is angled. In order to make a square cut, merely watch the mirror image on the plate. When the grain seems to continue straight through the blade as though the blade were made of glass, your cut is dead square and plumb as pictured below. Note the mirror image on the plate itself:

What is essentially happening is the blade is mirroring the grain opposite it and telling the user when it is oriented properly. That being said, if I were to tilt the blade laterally, the following effect is created:

Notice that the board does not continue straight through the plate but rather veers off aggressively. This tells me I am cutting on an angle. (This is exaggerated for the sake of the camera but this works down to show tiny differences in cuts).

The same is true if I were to angle the blade vertically as pictured here:

Notice that the grain slopes straight down indicating tilt in the blade. This effect is only achieved through a highly polished steel plate. After being spoiled by the polished Swedish steel featured on the Lie-Nielsen Dovetail Saw, I now consider this an essential element to any backsaw. It increases the accuracy of your cuts and removes some of the time associated with marking square lines. This feature is particularly helpful to a beginner because you can get a feel fairly quickly for how to hold the saw in order to achieve that proper reflection. When you cut, check for both square and plumb orientations before you take your cut. When you finish cutting, check your kerf for square, and if you have followed these steps and have a good quality saw that is set correctly, it will be dead on.

If you notice that the saw is naturally drifting, it is usually a sign that the set of your teeth is off. The set is essentially the amount that the saw teeth are pushed away from the plate. This ensures that the teeth that are cutting and creating a kerf generate one that is just slightly larger than the rest of the saw plate. This allows the user to make fine adjustments to the cut angle. If your saw is always drifting in one direction off your line, the set is likely too great on that side of the saw plate. Pick up a saw set and push the teeth on the other side of the plate to the same point. This will make sure the saw doesn't pull towards one side which can be frustrating and makes cuts inaccurate.

How to Take a Cut:

Cutting with a backsaw is very simple, but takes some practice. The first thing to learn is how to hold the saw. See the photo below: The index finger sticks forward and should not be wrapped around the handle with the rest of the fingers. Note: I am a lefty. Everything is convertible for a righty, though.

Before moving the saw at all, rest the saw on the endgrain and set your hand to align with the angle desired. You cannot make major changes in the angle of the cut once you start cutting because of the spine of the saw. Slight changes can be made, but the saw will track a perfectly straight line, so you want to set the saw at the desired angle before you start cutting. Some people advise one to start their cut by pulling the saw backwards, but this is a common mistake. If you take a minute to look closely at your saw teeth, you will see that they lean forward slightly. This is called “rake”. This is the direction in which the saw must be pushed in order for the teeth to bite wood.

Pulling backwards on the saw will cause the teeth to bounce and create an irregular kerf. The correct way to cut is to angle the saw up and lift the weight off the teeth so that the teeth just kiss the endgrain fibers as pictured below. In order to lift the weight off the saw, you should lift your wrist slightly. You will feel the saw pressure at the bottom of your hand by the crest when you are sawing correctly.

The saw is contacting the wood on the far side, but not on the side facing the user. You should stick your thumb next to the saw blade to guide it as pictured:

Then slowly take small nibbling strokes at the tip of the blade before lengthening the saw cut to using the entire blade. Take long even strokes without putting too much pressure on the saw. Let the saw do the work always. This will yield an excellent result that will create an accurate cut for joinery like dovetails and tenons without the cost and fuss of setting up a machine. No dust mask, hearing protection, or dust collection is needed.

Click here to visit the Highland Woodworking Hand Saw Department

Samuel Colchamiro is a hobbyist woodworker who lives in NJ and works solely with hand tools. He enjoys writing, and is hoping to share his woodworking expertise with others to make their woodworking experience more enjoyable. He can be reached at scolchbm@gmail.com.

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