Understanding Teeth Per Inch (TPI) When Choosing a Reciprocating Saw Blade
Teeth per inch (TPI) is one of the first specifications you’ll see when looking at reciprocating saw blades. As you might guess, TPI is an indication of the number of teeth on the blade, typically ranging from 6 to 24.
Understanding tooth count will help you find the best reciprocating saw blade for different jobs. Why is TPI important?
Blade TPI is a factor in performance. Blades with a lower TPI cut faster and more aggressively than blades with a higher tooth count. Blades with a higher TPI create a smoother cut.
Blade TPI is also a factor in the material the blade will cut. Blades with a lower TPI are more suitable for wood. They work well for demolition projects where speed and the ability to cut through lumber and nails is more important than a smooth finish. Blades with a higher TPI measurement are perfect for cutting wood when clean edges are important. They can also be suitable for cutting metal.
- A 6-TPI blade is good for pruning trees and will cut through a tree limb quickly. It’s often useful for demolition work as well when you might need to cut through lumber and nails before a remodel. You won’t need to worry about clean edges since you’ll be replacing the lumber or covering it with drywall, siding, etc.
- A 14-TPI blade works as a metal-cutting reciprocating saw blade, often allowing you to cut different types or thicknesses (gauges) of metal. Often these blades work on wood as well and offer a good balance of smooth cuts and speed.
- Higher-TPI blades, such as 18- and 24-TPI blades, are usually reserved for metal cutting.
A reciprocating blade set with different TPI specifications is an excellent choice for a do-it-yourselfer. A set gives you a range of options so you’ll be ready for a variety of cutting tasks.
How to Choose The Right Reciprocating Saw Blade Size
Along with TPI, reciprocating saw blade sizes — length, width and thickness — are other factors in finding the best blade for a project. Different materials and different uses require blades of different sizes, so it’s a good idea to have a variety.
Blade Length
Blade length determines the cut depth a reciprocating saw blade is capable of making. Longer blades make deeper cuts, so they can cut thicker material. The blade should be a couple of inches longer than the thickness of the material you need to cut. Standard lengths range from 4-inch blades to 12-inch blades, with 9-inch reciprocating saw blades being good, common choices for general DIY work.
Long blades can bend a bit and work well for flush cuts or cutting curves. A longer blade also cools better, which can give it a longer life. You’ll see longer blades used in pruning as well as heavy duty demolition work.
Shorter blades don’t flex as much as longer blades, so they cut more aggressively. You can usually control a shorter blade more easily and you’re more likely to get a straight cut. The rigidity of a short blade makes it work well on thicker metals and for starting cuts in material where you don’t have an edge or pilot hole (known as a plunge cut).
Blade Width
Like shorter blades, wider blades are more rigid and offer more stability than a comparable narrow blade. Manufacturers measure width across the face of the blade, from the teeth to the top of the blade, so wider blades have a higher profile. For demolition work, use a 3/4-inch-wide or wider blade. For cutting that requires a smoother finish or more careful work, choose a narrower, low-profile blade.
Blade Thickness
Manufacturers measure blade thickness across the edge of a blade. As with length and width, thickness is a factor in blade strength and rigidity. Blade thickness usually ranges from .035 inch to .050 inch or more.
Thinner blades are suited to general do-it-yourself work, detailed cutting and creating a smooth finish. Thicker, stronger blades let you do heavy-duty work and cut through tough, dense material. Thick blades create a wider cut (known as the kerf), removing more material than thin blades. Keep this in mind for work where measurements and cuts need to be exact.
Reciprocating Saw Blade Materials and Uses
Blade material is another factor in choosing the best reciprocating saw blade for an application.
Bi-Metal Blades
Bi-metal reciprocating saw blades combine two metals — one for the teeth and one for the body of the blade. For example, the blade teeth might be high-speed steel and the body carbon steel. High-speed steel teeth stay sharp longer than carbon steel teeth would, but the strength and flexibility of carbon steel creates a durable blade body.
Bi-metal blades work well for general cutting and, depending on the blade design, can cut metal, fiber cement and tile in addition to softer materials like wood and drywall.
Carbide Tooth Blades
Carbide tooth reciprocating saw blades also contain two materials, usually a steel blade with tips made of carbide attached to the ends of the teeth. The carbide material makes the teeth highly resistant to heat and exceptionally hard, creating a blade that lasts longer than bi-metal types.
These blades are perfect for cutting hard and thick metals and some can cut masonry products as well.
Carbide Grit Blades
Carbide grit reciprocating saw blades take advantage of the hardness and durability of carbide material, but these blades don’t have teeth. The grit is bonded to the blade surface. Since these blades don’t have teeth, there’s less risk of the blade getting stuck in the material.
These blades cut materials like tile, ceramics and brick.
Diamond Grit Blades
Diamond grit reciprocating saw blades are another type of blade that cuts with an abrasive surface rather than teeth. These particles are harder than carbide, creating a longer lasting but more expensive blade.
Diamond particles affixed to the blade can cut cast iron, stone and brick, letting you use your reciprocating saw as a masonry saw.
Reciprocating Saw Blade Frequently Asked Questions
Use the answers to these frequently asked reciprocating saw blade questions to help you find the best blades for your saw and get the best use from them.
Can I Use a Reciprocating Saw to Cut Tree Branches?
Yes, a reciprocating saw with a wood-cutting blade will cut tree branches you can reach from the ground. Check the saw manual and blade packaging for use and safety information, but in general, a 4- to 6-TPI blade with a length of 9 or 12 inches should work for pruning. Just make sure it’s a couple of inches longer than the diameter of the branches.
Do Reciprocating Saw Blades Fit All Saws?
No, reciprocating saw blades are not always interchangeable with different reciprocating saws. Often blades work only with a particular brand or saw model. You can find universal reciprocating blades that are designed to work with multiple saws, but make sure a blade is compatible with your saw before purchasing or attempting to install or use it.
How Do You Replace a Reciprocating Saw Blade?
Unplug the saw or disconnect the battery. Steps vary, but in general, loosen the blade clamp and pull the blade from the shank. Insert a new blade onto the positioning pin. Engage the clamp and ensure the blade is locked. Follow the instructions for your saw. Wear work gloves when handling blades. A blade gets hot with use, so let it cool before handling.
What Is the Longest Blade for a Reciprocating Saw?
The longest blade for a standard reciprocating saw is a 12-inch blade. While there may be longer blades available, they’re not typical and likely are for specific saws and applications. A saw blade should be just a couple of inches longer than the thickness of the material you’re cutting; a blade that’s too long will be more difficult to control.
Are Jigsaw Blades and Reciprocating Saw Blades the Same?
No, while jigsaw and reciprocating saw blades both cut with a reciprocating or back-and-forth action, they only work on specific tools. Jigsaw blades are narrow blades that allow jigsaws to make detailed cuts including circles and intricate shapes. Reciprocating saw blades fit reciprocating saws for heavy-duty work like cutting studs, metal pipe and masonry.
How Long Do Reciprocating Saw Blades Last?
Blade life depends on what you’re cutting and blade material. Cutting hard material can wear blades quickly. For comparable DIY work, carbide-tooth blades last longer than other toothed blades. Carbon blades wear the quickest. The hard cutting material on diamond grit blades makes them extremely long-lasting, but they’re not typical for DIY projects.