There is a basic question that every person that needs to use a saw must answer, ‘What’s the right saw for this job?’ In other words, what should you consider when choosing between a table saw or band saw for example.
In general, there are two categories of saw blades:
- Circular blades: found on the circular saw, miter saw, and table saw
- Straight blades: found on the band saw, jig saw and reciprocating saw
Keep in mind that there is no ‘holy grail’ when it comes to choosing a saw or saw blade. Each saw and blade has its place.
Picking the wrong blade can cause damage, adversely affect the quality of work, and be costlier in the long run. The right choice will produce better quality, smoother workflows, ensure your blades last longer, and keep you safe.
Before discussing the factors to consider when choosing the right blade, we first need to ensure that we are on the same page about one crucial point. That is, ‘how to saw teeth cut.’
Understanding the cutting mechanism of a saw will help you better understand the right saw blade to choose, let alone the right type of saw to pick.
How do saw teeth cut?
As the whole saw blade moves through a piece of material, each saw blade tooth acts like a tiny chisel. The rule of thumb, whichever type of saw you consider, is:
The higher the number of teeth on a blade the smoother and finer the finish. The lower the number of teeth on a blade the more aggressive and rougher the finish.
Typically, blades with fewer teeth have deeper spaces in-between the teeth (gullets), and this has the effect of aggressively chiseling through the material faster. A smoother and more delicate cut will take more time to accomplish because the gullets are shallow and the small teeth cut through a smaller amount of material.
Factors when choosing the right blade
Below are some crucial factors to consider:
1. Teeth-Per-Inch (TPI)
We have already discussed the general rule of thumb when choosing a blade. TPI adds some nuance to this rule.
Basically, TPI is simply the number of teeth across an inch of the saw blade starting from the center of a gullet (space in-between two teeth).
Based on the TPI, blades can be categorized into three.
Fine-toothed blades (10+ TPI)
- They have tiny teeth and the shallowest gullet
- They cut away the least amount of material per stroke
- They produce the smoothest finish but cut the slowest
- Material (g., sawdust) is more likely to accumulate between the teeth and make the blade less efficient
Medium-toothed blades (7-10 TPI)
- They have larger teeth and a deeper gullet than a fine-toothed blade
- They cut away more material per stroke than a fine-tooth blade
- They are aggressive, faster, and produce a rougher finish than a fine-toothed blade
- They are typically used on saws that do general purpose cutting
Coarse-toothed blades (1-7 TPI)
- They have the largest teeth and the deepest gullet
- They cut away the most amount of material per stroke.
- They produce the fastest cut but the roughest finish
2. The set of the blade
The set is basically the angle of the teeth relative to the plane of the blade. If the set is wider, then the cut will be more aggressive, and the kerf (the slot cut into the material by the saw), will be wider since more material will be cut away. Typically, the wider or more pronounced the set is, the lower the quality of the cut.
A fine-toothed blade with a more pronounced set can, therefore, cut faster than one with a less pronounced set. On the other hand, if you are working on costly material, a fine-toothed blade with a less pronounced set may be a better choice for you.
3. Blade thickness and kerf width
The kerf width isn’t just determined by the set of the blade but also by the thickness of the blade plate. Generally, a solid and reliable blade plate will also produce a neat/consistent kerf.
Also, consider that:
- The set of the blade has to be wide enough to allow the blade plate to pass through the kerf smoothly and make a true/accurate cut.
- The blade plate has to be thick enough to absorb vibration
- The blade must also properly handle the heat generated when cutting
- If the saw is not powerful enough (or if it is underpowered), excessive friction will heat up the blade, which could distort the blade or scorch the material being cut
4. The sharpness of the blade
A sharp blade will not only make cutting faster and easier, but it is also less likely going to cause saw blade burns on the material, even if it is a fine-toothed blade. Therefore, make sure that your blade is always sharp because it is more effective and will produce higher quality work.
5. Quality of the blade
Good quality blades don’t economize on steel or carbide. Their teeth are designed to be re-sharpened several times, and the blade is generally designed to last long. Poor quality blades are mostly thin.
Also, be aware of old technologies that could create noisy blades. Such blades often have expansion slots that bluntly end in open holes.
6. Type of blade
Depending on the type of cutting you want, there are three basic types of blades:
- Rip-cut blades: They have a low TPI count and are designed to cut in the same direction as the material. The tips of the teeth are flat-topped for efficient cutting.
- Crosscut blades: They have a high TPI count and are designed to cut perpendicular to the material. The tips of the teeth have alternating bevels (left -facing and right facing bevels).
- Combination blades: They are designed to adequately do both rip-cuts and crosscuts. They are mostly used for general tasks or by DIYer’s.
Conclusion
At the end of the day, putting into practice what you have learned here is the best way to make the information stick. In doing so, you will find your preferences, decisions will be easier, and you will produce better work.
Hopefully, the next time you have to decide between a table saw or band saw, or any other saw/blade for that matter, your decision will be that much easier to make.