An electric jigsaw is a fairly versatile tool that not only allows you to process various materials, but also perfectly copes with both delicate operations and high-speed sawing. For this there is a wide range of a wide variety of paintings..
Manufacturers of power tools also supply consumers with consumables for it, so it is not surprising that the saw blades are not unified. Free use of saws in jigsaws of different brands does not allow differences in the shape of the shanks, of which there are currently three most common types:
U-shaped shank is typical for original tools made in the USA and Europe. Suitable for all jigsaws with collet and screw clamping.
Shank proprietary Makita – an obsolete type of shank for the original Japanese tool, notable for the presence of two holes. At the moment, jigsaws with this type of clamp are not produced, however, consumables on sale can be found.
The T-shaped shank is the most common due to the popularity of branded tools from Bosch, Makita, DeWalt and similar companies, whose production facilities are located in the PRC. Used in clip-on jigsaws.
There are also hybrid solutions. For example, U-shank saw blades with two holes and suitable for old Makita jigsaws are quite common. Also, the tool with the FastFix quick-fix clamp is gaining great popularity, for which the shape of the shank does not matter, but there are restrictions on the thickness.
In addition to the shank, the shape of the spout can also change. The standard nose of the file has a bevel at the edge from the working part to the back of the head, while the first few teeth are missing. There are also files, in which the nose has a complex shape, reminiscent of an eagle’s beak. Such blades are called submersible, they are used to start cutting from the center of the workpiece, and not from the edge, however, such an option should be provided by the capabilities of a jigsaw.
Types of teeth and set
Like conventional hand-held hacksaws, jigsaw blades can vary in shape, size and pitch, sharpening angle and set pattern. In this regard, jigsaw blades are even more diverse than manual ones..
The rounded shape at the base of the teeth determines the purpose of the blade for sawing solid wood, as a rule, such saws are used in carpentry for high-speed cuts without claims to cleanliness. Saw blades with wedge-shaped teeth form less chips, but the sawing speed is much lower, this type of blade is most often used for cutting chipboards. The triangular shape of the teeth is typical for blades designed for sawing thin sheet materials, including metal and plastic. If the saw’s teeth resemble a claw in shape, it is intended for cutting drywall, LSU, cement-bonded particleboards and other materials containing mineral abrasive substances.
The pitch and size of the teeth can be indicated by a number indicating the distance between the vertices in millimeters, or an off-system unit TPI (Tooth Per Inch), which indicates the number of teeth per inch of blade length. TPI of 10–12 (pitch 2–2.5 mm) is considered a fine tooth and is typical for blades used for sawing metal and finishing cuts on laminated fiberboard and chipboard. With a tooth pitch of 2.5–4 mm (TPI 6–10), the blade is considered to be of medium hardness, usually used when cutting wood parts with minimal subsequent processing. The roughest blades have a TPI of less than 6 (pitch over 4 mm) and are designed for rough high-speed cutting.
Files for an electric jigsaw can have one of four types of wiring: classic faceted, classic ground, internal and wavy. The classic ground cut has a shallower angle of attack and a wider cutting edge, making it better suited for sawing softwood along grain and wood-based materials. The faceted tooth shape provides improved chip ejection and is therefore well suited for sawing plastics as well as laminated materials. The wave-like layout helps to reduce the contact patch of the blade with the edges of the cut, thereby reducing heating during operation, which is especially useful when sawing hard and dense materials: steel, fiberglass, non-ferrous metals. With internal setting, the teeth do not protrude beyond the blade profile, due to which a higher quality of cut edges is ensured, but at the same time the cutting speed is one of the lowest.
Blade length and width
Separately, it is worth touching on the dimensions of the saw blade itself. At first glance, the larger it is, the better, but there are several subtle points in this matter..
The blade length should be selected in accordance with the thickness of the workpiece being cut. If you cut relatively thin materials with a long blade, a significant part of the teeth will not be used, respectively, the profitability of the consumable will greatly decrease. In this case, the choice of a long file should be done with an eye to the effective cutting depth: the projection of the blade above the base of the jigsaw in the upper position of the pendulum should exceed the thickness of the material to be cut by 2-3 teeth.
The width of the blade determines the stability of its position during operation. The more extended the back of the head, the easier it is to keep the tool in line with the cut. However, in this case, the friction contact patch also increases, which increases the risk of overheating the file during operation. In general, blades 5–7 mm long are used for curved cuts and fine sawing of laminated materials. Blades up to 14-16 mm are used for direct high-speed cutting of wood, where the quality of the edges is not important, however, the teeth must have a pronounced setting. There are also saber blades up to 40–45 mm wide. They are quite thin, have relief holes in the back of the head and are designed for even cutting of thin sheet materials..
The thickness of the blade determines its ability to withstand the force exerted on the tool during high-speed cutting. Most canvases are in the range of 1.1–1.5 mm, but there are exceptions. For example, files with a thickness of 0.9 mm are used for through carving in wood: they are somewhat easier to hold in a perpendicular position and allow a smaller turning radius. On the other hand, there are special blades up to 4 mm thick for high-speed roughing, but their use is only possible if the jigsaw has a suitable clamp and guide mechanism. You also need to remember that for almost all canvases the thickness of the back of the head is indicated, while with an external setting of the teeth, the cut line will be slightly thicker.
Basically, the marking of saw blades is applied to the shank and consists of one Latin letter, three numbers followed by one to three additional Latin letters. The first letter identifies the type of shank: T-shaped, U-shaped, M – specialized Makita. It is worth remembering that for some canvases the first letter may be absent altogether or be replaced by the manufacturer’s symbol, for example, DW – DeWalt.
Jigsaw files marking
Of the numbers in the designation, the first one determines the length of the web: 1 – up to 75 mm, 2 – 75–90 mm, 3 – 90–150 mm, 4 – over 150 mm. The next two numbers determine the purpose of the blade according to the manufacturer’s specification: for a straight, curved or fine cut, for wood or metal, etc. More clarity on this issue will be made by the saw blade marking table of a particular manufacturer. The last letters define the special characteristics of the canvases. For example, F – bimetallic blade (hardened tooth and high carbon occipital part), R – reverse direction of teeth, O – tapered occipital part, X – teeth of several sizes.
Additional markings can be applied to the canvas itself, while it often turns out to be much more understandable, but the designations are not standardized. So, on the blade, the grade of steel from which the blade is made can be indicated: HSS – high-speed, HCS – hardened, BM – bimetal, HM – carbide. Domestic brands indicate the purpose of the blade directly: for laminate, for wood, for metal, etc. The Bosch brand marking is also famous: the first part of the marking (basic, clean, progressive, speed) determines the type of blade and the nature of the cutting mode, followed by a separator for, followed by the material to work with: metall, wood, ceramic, etc..
Special types of canvases
In conclusion, you should talk about the special types of canvases. In the above Bosch marking in the first part, the word Special is indicated, using this series as an example, we will consider these specific varieties. In addition to the above mentioned saws with hard-alloy claw teeth for drywall and materials with mineral filler, the following types can be distinguished:
- For ceramics – with diamond coating on the working part.
- For stainless steel – special form of sharpening and material of teeth.
- For plastic and fiberglass – fine tooth and special wiring, excluding material melting.
- For foam – increased length and reduced thickness of the web.
- For soft materials such as corrugated board or rubber – a blade without teeth, in fact, representing a wavy knife.