November 17, 2021

What is TPI for Resawing?

What is TPI?

TPI stands for “teeth per inch,” which refers to the number of teeth on a saw blade in each inch of the blade. The TPI you need will depend on the material you are cutting. For cutting wood or other soft materials, a saw blade with a TPI between 6 and 20 is recommended. A TPI between 14 and 36 is more appropriate for harder materials like metal. The TPI number can usually be found on the saw blade itself. For more information on choosing the best bandsaw for resawing, check out our helpful guide.

Why is it important for resawing

  • Resawing is important when you work with large or thick stocks of wood, and it makes cutting a thick wood stock along the grain and parallel to the broader face of the wood into two or thinner pieces bearable.
  • It helps you produce book-match pieces for cabinet-making or other furniture projects.

Thinner blades for more speed, or wider blades for less vibration

Blades with more teeth cut slower and smoother, and saw blades with fewer teeth cut faster and had a slightly rougher finish. FUsing a finer saw blade for thinner metals and plastics under ¼ inch (18 – 32 TPI). 

Wider blades are more stable and resist bending and vibration to provide straighter, more aggressive cuts. They have extra support that makes wider blades better for heavy-duty applications.

Blades with a lower width are more flexible for finer cutting. They range from ½ to ¾ inches. Lower TPI blades cut fast but leave rougher edges, whereas saw blades with higher TPI remove smaller amounts of material with each pass. That is why they cut slower and leave a much smoother edge. 

Thicker blades are more durable, resist bending and vibration, and allow a heavier feed pressure for tougher jobs. They are for applications where fine cutting or flexibility is required.

Common TPIs for each blade thickness

Select the correct Teeth Per Inch (TPI) for the thickness of the material you are cutting. Using the correct TPI increases the life of the blade. Refer to the chart when you are not sure. The number of TPI defines the pitch of the saw blade, and it varies from 1 to 32 TPI. 

Some bandsaw blades have different pitches on the same saw blade, known as Vari-Pitch. TPI measures from gullet to gullet, not tooth tip to tooth tip. For wood and soft materials, aim for 3 – 6 teeth in the workpiece and  6 – 24 teeth for metals.

Resawing on a Band Saw

Use the right blade and proper setup to cut the stock to any thickness. Install the correct blade type for cutting through the width of a board. Resawing involves making rip cuts in the face of a wide board. 

Like on the table saw, select a blade with fewer teeth per inch (TPI) than the blades you use for crosscutting or cutting curves. The standard tool is 14 inches with a 1 ⁄ 2-inch wide blade with 2-3 TPI.

When you have mounted the blade in your saw, adjust the tension. Never rely on the scale on your saw since it is not a reliable indicator of how much blade tension is required. However, when set, the blade tension keeps the blade rigid enough to cut through a wide workpiece without deflecting.

Make sure the table is square to the blade and follow the instructions in the manual as you set the thrust bearings and guides. When resawing, pay attention to the fence. You easily make one if your saw did not have a saw fence. 

A tall fence clamps to the saw table and supports the workpiece. That is necessary when resawing thin stock.

However, combining a fence and a blade drift gives you a better straight cut. When cutting, the band saw blades veer slightly to the left or right, so you need blade drift. The drift varies with every saw blade, and you can compensate for it by clamping your fence to match the drift angle. 

Resawing with a Tablesaw

When preparing 1⁄4″ thick stock for a project, you can do it on your table saw. Even 10-inch table saws easily resaw boards up to 5 1⁄2″ wide. Outfit your table saw with a zero-clearance insert equipped with a 1⁄8 inches hardboard splitter that protrudes 3⁄4 inches above the surface of the insert. 

Make a 3×8-inch push block with a 3/8-inch notch 6 inches long from stock, at least as thick as the stock to be resawn. Adjust the blade height to 13⁄16 to clear the splitter, center the wood stock on the blade, and make the first cut. Make additional saw cuts as you raise the saw blade each time until the depth of the saw cut is over half the width of the stock you are resawing.

Flip the stock end-for-end, and keep the same side against the fence. Repeat the cutting procedure on the other edge until the stock is sawn in half. Push both pieces of the resawn stock past the splitter with the push block.

Is more TPI better?

The higher the amount of saw blade teeth, the better the quality of cut and finishing. A saw blade with fewer teeth will be more suitable if you want a faster and rougher cut. For aluminum or a high-quality finish, use a higher number of teeth compared to blades for softwood.

When blades have fewer teeth, they have deeper gullets. That refers to the space between teeth, creating a more aggressive chiseling action. Tungsten-Carbide Tipped blades have gullets with a unique shape compared to standard gullets. That is why they have reduced vibration and noise while cutting. The heat on the steel center is minimized, making it safer for the user.

How do you measure TPI on a hand saw?

When purchasing saws, the TPI is in the product spec; however, sometimes, you need to find the number yourself. When measuring TPI, always begin the measurement in the center of the gullet.

Measure one inch along the blade, and that is from the center of the gullet. Saw blade with two teeth per inch and start counting the teeth. Count the number of teeth in that 1-inch space, the blade’s TPI. However, the blade’s TPI may not always be a whole number.

What is a scoring blade for?

A scoring blade is a small blade in front of the main saw blade. It cuts a kerf wider than the main blade. When installing, the teeth point backward and turn the opposite way. It is set low enough to nick, or score, the bottom surface of the material.

The cutting edge of the knife is hard material such as tungsten carbide. A scoring blade makes a clean-cut and cuts through the material’s underside. However, the upper face of the material remains uncut because it remains untouched by the scoring blade.

It prevents tearing out and chipping. You can also score both sides using the scoring blade. In doing so, you will get a crisp cut on both sides. Standard table saws have 40 or 50 teeth, and these cut across or with the grains. Keep the blades clean, sharp, and of good quality.

David D. Hughes

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