Teeth per inch, or TPI, refer to the number of teeth that are located on one inch of the jigsaw blade. The TPI of the blade will determine the speed at which the jigsaw will make the cut, as well as the smoothness of that cut. Using an incorrect TPI for the material that you’ll cut with the jigsaw can lead to the formation of splinters in the wood, or the jigsaw blade may wander off of the marked line.
Blades with a low TPI has fewer teeth than blades with more higher TPI ratings. Because of the fewer number of teeth on these blades, a large amount of the material can be removed from the cutting surface with each stroke of the jigsaw. These types of blades are utilized when cutting thick pieces of softwood, as the high cutting speeds enabled by the low TPI blades allow for faster cutting.
How to Choose the Right Jigsaw Blade
However, the edges created with these blades are often rough, and you should do additional sanding after cutting with these blades. Blades with high TPI have a high number of teeth along the cutting surface of the blade. These types of blades are utilized when cutting thin metal or thin plastic.
The high number of teeth allow for precise cutting of the material, but the cutting speed with high TPI blades is slower than with the low TPI blades. It is essential to ensure that at least three teeth on the jigsaw blade are in contact with the material being cut. If fewer than three teeth is in contact with the material, the jigsaw blade may cause pinching of the material.
If too many teeth are in contact with the material, the jigsaw blade may bog down while cutting into the material. The material of the blade is another important factor in the performance of the jigsaw blade. Jigsaw blades with high carbon steel blades are used to cut materials like wood and composites.
Carbon steel is a flexible metal that is relatively inexpensive. High speed steel is used on blades that are to cut metal, and the high speed steel resist heat to prevent the teeth from softening during the cutting process. Bi-metal jigsaw blades are metal blades that have a flexible metal body and metal teeth.
Bi-metal blades are useful for cutting wood that has hidden nails. Finally, blades with carbide grit are used to cut tile or cement board. The grit on the blade grounds at the point of contact with the material being cut.
The shank of the jigsaw blade must match the shank of the jigsaw tool that you use. T-shaped shanks are common on moddern jigsaws, as the T-shaped shanks allow for blades to be changed without the use an wrench. The older models of jigsaws tend to have U-shaped shanks, which require a screw to be inserted into the jig to secure the blade to the jig.
The length of the blade is also important. If the blade is too short, the blade may chatter against the material. If the blade is too long, it may whip around when the jigsaw blade is cutting curves.
The orbital setting of the jigsaw blade determines the movement of the blade. When the orbital setting of the jigsaw is set to 0, the blade will move in a straight line up and down, which is important when cutting metal to prevent burning the edges of the metal with heat created from the orbital movement. When the orbital movement of the jigsaw is set to a higher number, the blade will move forward in a swinging motion.
This is appropriate for cutting wood, as the forward movement increase the cutting speed of the tool. Many people set the orbital speed of the jigsaw blade to a setting of 1 or 2, which provides an even balance between cutting speed and the finish of the cut. It is important to be able to correctly identify the material that is to be cut.
For instance, softwood requires the use of a medium TPI jigsaw blade and an aggressive orbital cutting setting, while hardwoods requires the use of a jigsaw blade with a higher TPI and higher precision. Additionally, plastic and aluminum materials require a wavy set jigsaw blade to prevent the material from pinching the blade. Before beginning to cut the materials of interest, it is important to test the blade on a piece of scrap material.
Additionally, the blade should be replaced when the blade become dull. A dull blade will cause the jigsaw to drag the cutting of the material along, which may lead to burning the material. Finally, tape can be applied to the area of delicate surfaces to prevent the formation of splinters, and you can apply oil to metal to reduce the friction between the blade and the metal.
