Hand saws are only useful when they are sharp. They have one purpose, to cut material, and if left to dull, they cannot perform that task. Knowing how to sharpen a hand saw is an art, so learning hand saw sharpening is crucial to keeping your tool in tip-top condition.
We show you the best techniques to get the best result from hand saw sharpening.
Sharpening Hand Saws
Hand saws are sharpened with tapered files. There are crosscut teeth and rip cut teeth. Each is set in different ways. Always examine the saw blade for uneven teeth. This is called jointing. Clamp the saw blade in a vice for added support, and use a saw set to realign the teeth. Each saw requires a slightly different filing method.
Types of Hand Saw Teeth
Essentially, there are two types of hand saw teeth. Both cut into wood using different methods.
Crosscut teeth are angled on the inside edge to make them better at cutting across the fibers of the wood. This type of teeth set improves the blades ability to slice through the wood like a series of tiny knives.
Cutting across the grain is generally considered a more difficult task.
Rip Cut Teeth
Rip cut teeth do not have an angled edge. Instead, the teeth act like chisels, scraping the wood away as it moves through the material. These teeth rip through the wood along the grain, which is considered an easier task than crosscutting.
How to Choose the Type of Saw File
Saw files come in four basic tapers: regular, slim, extra-slim and double extra-slim. They also vary in quality. Chinese-made files are generally cheaper and softer, meaning that you get a substandard result. Take the time to find quality tools and spend the extra cash.
The rule of thumb for sizing the file is that it should be no bigger or smaller than you need. You should be able to see the teeth on the blade as you file, and there should be no under or overlap of each edge of the file.
A file that is too small will only sharpen using the same middle sections of each face of the file. This could have the effect of dulling instead of sharpening.
On the other hand, a file that is too large will obscure the teeth. As a result, they rarely deliver the same quality of sharpness when compared to smaller files.
You can judge the size of the file you need by the saw blade’s points per inch, or teeth per inch.
Here is a handy chart:
|File Type||Teeth Per Inch (TPI)|
|8-inch regular taper||3 to 4.5|
|6-inch regular taper||5 to 5.5|
|7-inch slim taper||6 to 7|
|6-inch slim taper||8|
|6-inch extra-slim taper||9 to 10|
|6-inch 2x slim taper||11 to 13|
|4-inch 2x slim taper||13 to 20|
What You Need
- A set of taper files.
- A saw set.
- A vice.
- Spare wood.
- A mill file.
How to Sharpen a Crosscut Saw
1. Inspect the Saw
Make sure that all of the teeth are level. If you have variations in the teeth, you need to get them all to the same level. This process is known as jointing. Clamp the saw into the vice, using two strips of wood to support the blade and to add rigidity.
Make sure the teeth protrude 2 inches above the top of the vice. Grab the mill file and starting from the heel end of the blade, run it down the tooth line towards the toe. It should flatten the facets and leave a uniform line. Use three or four strokes to perfect the line.
The benefit of jointing is that it creates a flat surface at each tooth point to guide your work when you start sharpening the saw blade.
2. Set the Teeth
Saw sets are plier-like tools with long handles and a clamp at the other end. The pressure to angle the teeth comes from a winding mechanism that acts like a hammer against an anvil. When you squeeze the handles together, you will see movement in the tooth.
Place the saw set so that the center hammer (the metal winding mechanism that bends the tooth against the anvil) aligns with the point of the tooth and squeeze. The tooth will move away from you. Repeat this process on every other tooth, then flip the saw blade and work along the teeth that you missed out.
3. Put on Your Safety Equipment
Put on your goggles and reclamp your saw in the vice. Make sure the bottom of the gullets are 0.063 inches above the top of the vice. Now place the taper file in between the first pair of teeth. You should have a tooth set towards the right of you and another away from you to the left.
4. Start Filing
With your index finger pressed firmly on the file at the point where it meets the tooth, push the file down into the gullet. This should rotate the file into the gullet at an angle that matches the 15 degrees of the crosscut teeth.
Maintain the bevel angle and take your first stroke, making sure the file stays in the gullet. You are aiming to reduce the flat on the front and back teeth by half.
5. Skip the Next Tooth
Skip a gullet and repeat the same process, using a uniformed number of strokes. The reason why you miss out a tooth is because they are set in reverse. So when you get to the end of the blade, you can start with the first gullet you skipped and work along the blade. Just make sure that the set on the left is facing towards you and the right faces away.
To get the neatest finish on the blade, you need to get a block of India stone at 600 grit, and with the saw placed flat on the table, run the stone along its edge. This evens the set and removes any burrs created by the filing process.
Flip the blade over and do the same to the other side, making sure you use gentle pressure.
Blade Quality Test
How to Sharpen a Rip Cut Saw
1. Clamp the Saw
In the same way you clamped the crosscut saw, make sure you use two strips of wood to add support to the blade while it is in the clamp. You should set the height of the gullets at the same as the crosscut saw, at 0.063 inches. Make sure the saw heel is on your right.
2. Place the File in the First Gullet
Place the file in the first gullet, ensuring it is firmly seated to the bottom. Hold the file perpendicular to the saw blade, so the file is flat with the table.
3. Start Filing
With your first stroke, push the file across the saw blade, making sure you use gentle pressure and the entire surface of the saw.
4. Keep the Strokes Fluid
Novices tend to make short, jerky strokes that result in an uneven finish. We need long, flowing strokes of even pressure, with a uniform amount of passes along the blade edge.
When you pass the file across the gullet, you should see fresh steel appear on the front and back of the teeth that straddle the gullet, as well as the gullet itself.
Continue filing until you see the flat disappear on the right-hand side. When you are satisfied, move to the next tooth in the sequence and repeat the process. Work along the blade until you reach the end.
Hand Saw Maintenance Tips
Looking after your hand saw will prolong the need to resharpen the blade. So, here are some sensible things you can do to slow the dulling process and preserve the integrity of your hand saw.
Store in a Moisture-Free Toolbox
Moisture causes rust, and rust damages your hand saw blade. The best way to avoid corrosion is to keep humidity at bay with an airtight toolbox.
Oil the Blade
Keeping the blade well oiled between uses keeps the rust at bay and protects the saw from moisture. It also keeps the saw lubricated when in use to make smoother cuts.
Remove the Rust
You can remove the rust using either a razor blade or sandpaper. Both scrape away the layer of corrosion to leave you with a cleaner blade.
Use the Saw Correctly
Make long strokes through the material. This gives you a smoother cutting experience and evens out the strain on the teeth. It means that the load is spread along the edge of the saw and not focused to one area.
Use the Correct Saw
Choosing the wrong saw for the task is a sure-fire way to damage the teeth. If the material is too hard, you will dull the cutting edge very quickly.
Give Your Saw a Hand
All tools need attention, but some need more than others. Hand saws are robust and will last a lifetime if they are carefully maintained. Keeping your saw in the best condition means having the best tool for the job, and the most professional finish to your projects. Who wouldn’t want that?