- Cutting tools and mechanics of their work
- Choice of saw blades and blades
- Zero-clearance technique
- Using adhesive tapes
- Ensuring a perfectly clean cut
It is believed that a high-quality cut of wood or sheet materials cannot be performed without a professional tool. Today we will tell you about ways to make a clean, even cut without chips, on our own and without using expensive equipment and consumables.
Cutting tools and mechanics of their work
Apart from stationary sawing machines, there are not many alternatives for manual work. Of the available tools, you can offer circular and pendulum saws, in the common people referred to as crosscutters and jigsaws. It is also possible to perform a sufficiently high-quality cut using a grinder, on which a saw blade for wood with victorious teeth is installed. But this is not the most effective and, moreover, far from safe option..
In the process of cutting with any type of power tool, the working bodies move at a very high speed, and therefore the machining mechanics remain, as it were, behind the scenes. However, understanding it is the key to getting a clean, chip-free edge. The simplest principle is the basis for the work of pendulum saws. The cut is carried out with the direct movement of the saw blade, while the size of the removed fragments completely depends on the size of the tooth and its setting.
Chips appear due to the heterogeneity of the processed material, in particular due to the hard crust of laminated sheet materials or due to the fact that the fibers of solid wood have different densities. Chips can form from different sides of the product, depending on the shape of the tooth, feed force and speed of the tool. When working with a jigsaw, the appearance of chips is due either to the fact that the teeth pull out large fragments from the seamy side, or due to the pushing of the upper layer, in which it is not cut off, but breaks out in large fragments.
The work of the teeth of a circular disc is in many ways similar to a jigsaw, with the only exception that their movement is directed strictly in one direction, and they move at a very high speed. Also a significant factor is the direction (angle) of the applied force: if the jigsaw saw moves strictly perpendicular to the surface, then the circular cuts at an arbitrary angle, depending on both the diameter of the disc and the thickness of the part. This can play into the hands: the oblique immersion of the tooth contributes to a more accurate cutting of the chips, but from the back side, due to the tangential movement of the cutting edges, rather large fragments can be pulled out. Of course, a circular saw will only be able to make a straight cut.
Choice of saw blades and blades
When cutting, cleanliness and processing speed are inversely related. It is worth noting that chips on the cut will appear in any case, so the main task is to reduce their size to such a value where they can be easily eliminated by subsequent processing. The smaller the size of the tooth and the closer to the right angle at which the cutting edge touches the surface of the material, the smaller the size of the chips will be. These are two of the three most important factors for choosing a circular saw blade..
The third can be called the setting value – the offset of adjacent teeth, which is quite simple to determine by attaching a ruler to them. To ensure a clean cut, the wiring should be minimal, but do not forget that in this case, when you try to cut a thick board or a sheet of plywood, the disc can be trivially clamped or the end will burn from strong friction.
Jigsaw saw blades are more varied. For chip-free cuts, a series of clean-cut saws are used, for example, BOSCH has a line of blades called CleanWood. Their main difference is their small size and the absence of a pronounced orientation of the teeth. They are usually in the shape of an isosceles triangle and cut in both directions of travel..
Also saws for a clean cut are distinguished by the almost complete absence of setting and the opposite direction of sharpening adjacent teeth. In order to ensure the possibility of a curly cut with small wiring, the files have a very small width, which makes them quite fragile.
For finishing cutting of sheet materials, canvases designed for working with metal products can also be used. These saws have the smallest tooth size known, so the cut is slow, but with the highest quality. Due to the considerable width of the canvases for metal, a fine figured cut can be carried out only with a significant bending radius, on average about 60-80 cm.
Note also that the bluntness of the teeth, which is characteristic of low-quality saws with a run of 3-5 meters, also leads to chipping. Therefore, do not skimp when purchasing consumables if the quality of processing is really important to you..
Carpentry craftsmen most often use the principle of finalizing the sole of the cutting tool, which consists in reducing the gap between the working body and the pressure pad. This is almost guaranteed to eliminate the crust breaking effect in the top layer of the material..
Zero clearance is achieved by attaching the cover plate to the tool base plate. The pad has only one narrow hole (or slot) that fits snugly against the cutting body. Because of this, even with a high feed force, the teeth are guaranteed to cut small chips, and not turn out the chips in the upper layer of the part..
When using pads, it is imperative that they do not scratch or damage the surface of the part. Therefore, most often they are made from a material that is inferior in hardness to the processed one, for example, MDF or drywall. Unfortunately, such an overlay is not enough for a long time, which is why it has to be changed every 4–5 meters of the cut.
More durable pads can be made of sheet plastic (PVC, fluoroplastic), fiberglass or metal. In the latter case, the surface of the pad must be carefully polished and soft metals such as aluminum or duralumin should be used to reduce vibration..
Using adhesive tapes
The same principle can be used to protect the back of the cut material. Tape should be glued along the cutting line, which will protect against pulling out large fragments. Pasting surfaces is one of the few ways to ensure the cleanliness of a figured cut with a jigsaw. Unfortunately, masking tape is not suitable for this in the best way due to its low strength..
The best quality cut can be obtained by pasting the part with aluminum or fiberglass-reinforced tape-tape. It should be wide enough to cover 15–20 mm on each side of the cut line. The density of the sticker is also important: the tape must be well pressed with a dry rag swab and by any means to exclude the formation of folds.
Tapes with very tenacious glue should be avoided. In the process of tearing off, they can carry along with them small fibers and fragments of the laminated surface, dissected by microcracks that form during cutting. Also note how easy it is to remove glue marks and whether the adhesive adhesion is good enough for rough materials like raw plywood or OSB..
Ensuring a perfectly clean cut
For most parts, it is sufficient to reduce the chip size to 0.2–0.5 mm. Such small irregularities of the cut edge are not striking, if desired, they can be easily eliminated by chamfering with an emery bar or smearing with a wax pencil-corrector. It is also possible to grind the end face with emery paper if a sufficient allowance value was given during cutting.
Nevertheless, even at home, it is possible to achieve a cut quality comparable to that of a saw with two high-speed discs. This is possible only when the tool moves along the guide rail, in extreme cases – along the temporary stop bar.
First, you need to make two notches about 0.5 mm deep on both sides of the part to indicate the thickness of the cut. Along the edges of the cutting line, you need to scratch two grooves under a straight ruler. This is done either with a segmented or oblique boot knife (for chipboard and uncoated wood) or with a sharpened drill or victorious cutter (for laminated materials).
The depth of the grooves should be at least half the thickness of the outer layer, which is inhomogeneous with respect to the main body of material. This method requires high accuracy of matching the grooves and the cutting line, but this is the only way to ensure a perfectly flat edged end that does not require additional processing.