A Jig Saw or keyhole saw it is a portable cutting machine that, together with a saw blade with reciprocating movements (down – up) and, in some models also with pendulum-type movements (down – up with a forward movement), allows us to easily make cuts straight or curved on almost any surface. The jigsaws or also calls jigsaw, are generally used to cut wood-chipboards, but by placing the appropriate saw blade, we can also cut metal and plastic materials.
Thanks to existing technologies, today it is possible to have various models of jig saws wireless. These models considerably facilitate the mobility of users, as well as the execution of tasks. Models jig saws, have reached the market offering the advantageous characteristic of not requiring an electrical connection.
Parts of a Jig Saw
one- Speed variator
3- Visor / cut protector
4- Adjustable cutting angle 0º to 45º
5- Saw blade
6- Trigger lock button
7- Orbital action selector
On the other hand, some saw models jigsaw They feature LED light to illuminate the cutting area, an integrated plastic slide insert to protect sensitive workpieces, cut line indicator for exact cuts, parallel guide, guide line and chip guard.
All these implements have been included in the recent or new models of jig saws, in order to protect users, make their work easier and to protect work materials that require it.
Cutting depth and blade types
The depth and type of cut is given by the blade type used, as well as the type of material to be cut. Check with the equipment manufacturer for the maximum cutting width and the type of saw to be used.
The large tooth blades give an alternating cut and are generally used for woods and derivatives, in boards up to 60mm. Those with medium teeth, give a more precise and fine cut, for wood, plates and plastic materials. Instead, a corrugated blade provides a straight cut for ferrous metals.
The saw blades with fine teeth, they give a fine cut, to contour closed curves in woods. We use the very fine teeth to cut soft and non-ferrous materials and lastly, the extra fine teeth, to cut metals.
Some models of Jig Saw They allow cuts with variable depths depending on the material, for example: In 80 or 85 mm wood, in 12 mm plastic, in 8 or 10 mm steel. They also allow for oblique cuts of a maximum 45 °, and conical cuts of a maximum of 47 °.
As an added feature, the design of some jigsaws allows you to change the cutting blade, without using any tools.
Some jig saws They are provided with an air duct at the back of the blade, which blows a jet of air, and in this way blows the debris into the cut line. Others, generally of the industrial type, come with a suction system. In some cases and especially in domestic type machines, we can find a support to place the vacuum cleaner spout.
Some models have a design that allows them to suction dust, using an adapter.
Speed in one Jig Saw is given by the number of oscillations per minute.
Generally, the models of jigsaws without speed regulator they are used for wood cuts where the maximum speed of the machine is used.
Variable speed drives allow us to select a certain oscillation speed, which depending on the model, type and brand of the saw, can give between 0 and 3000 oscillations per minute, to adapt in this way to the material being worked.
For the cutting of plastics and soft metals, the medium speed would be used, while the minimum speed is left for the cutting of ceramics or tiles. In practice, the sound of the saw and the ease with which it cuts will be the best indicators to choose a certain number of oscillations per minute.
To optimize the execution of cuts, some jigsaws They feature high running stability for precise cuts. They also feature a selectable pendulum lift for quick cuts. In some cases the pendulum function has 4 levels.
In order not to overheat the motor, it is recommended to let the machine rest after periods of mowing. In the case of using the low speed for a long time, it is convenient to run without cutting at the maximum speed to allow the motor to cool down.
In various models, we will find a button on the handle that, when pressed, locks the trigger so that in this way, the Jig Saw work continuously and avoid fatigue when we have to make prolonged cuts (this button is also found in various machines, such as drills, portable grinders, etc).
Currently, we will find models of jigsaws They come supplied with a laser that serves as a cutting guide. The laser is aligned to the cutting blade and its light points to the surface that we are cutting, in front of the blade. With the flick of a switch, we’ll get an excellent guide.
The following points will help us to achieve a good job:
- Before starting, draw the cutting line to follow.
- If possible, fix the piece to prevent it from moving. The back and forth movements of the jigsaw produce many vibrations.
- The blade of the Jig Saw It has an upward direction, therefore it tends to leave chips on both sides, but achieving a sharper cut in the area below. Therefore, when cutting, place the “good or visible” side face down. Therefore, we must put the piece inside out, to ensure that the piece is neater on the right side.
- Lateral guide: to make the straight cut, we can use the parallel guide of the machine, or place a guide rule well fixed and aligned to the saw blade. If it is not held well, we can make faulty cuts and we can even enter the saw blade on the guide, breaking it. Verify that the guide is not short. Otherwise it should be prolonged. When placing the guide, take into account the thickness of the sheet and that it is on the side of the “waste” material. In the event that we do not have a guide, parallel to the cutting line, mark a line for the external part of the metal base of the Jig Saw. This will serve as a guide, when the cutting line is covered with sawdust while we make the cut.
- It should always be cut on the disposable part of the cut, so that any excess can be removed with a brush, rasp or by polishing.
- To cut plastic, we will use reduced speed, to prevent the heat from melting the plastic.
- For cutting, a regular rhythm is used at intermediate speed, without exerting pressure, since this alters the normal cut of the blade, forcing the machine.
- Adapt the cutting speed according to the material.
- Always use blades in good condition, suitable for the material to be cut.
- To cut fragile surfaces without the risk of scratching them, we put masking tape on the feet of the jigsaw.
- To reduce jagged and jagged edges on plastic laminate chipboards, use a special reverse serrated laminate sheet. If you do not have a reverse-toothed blade, a fine-toothed blade could be used to cut metals, but by placing the board upside down and holding it well at its ends. In this way we will avoid excessive deterioration of the edges.
- When cutting metal sheets, in addition to using the appropriate blade, apply a layer of oil in front of the blade, so that it works as a lubricant. Cutting metal is work that must be done slowly, so do not force the machine. Wear hearing protectors and goggles.
- Ceramic cutting is done with special carbide blades, at slow speed. As when cutting sheet metal, the machine should not be forced.
- In cutting large areas, it is necessary to interrupt the task frequently to cool the saw blade and avoid overheating the motor.
- Free cuts, without workbench: the front part of the jigsaw must rest – without supporting the blade – on the piece to be cut. Align the saw with the line of cut. Turn on the saw and insert it into the piece, continuously holding the excess. The saw blade must be on the waste or excess side of the piece to be cut, as indicated in point 6. Advance evenly without forcing. When you get to the last few inches of cut, slow down.
- For a uniform and neat finish, the pressure applied must be reduced as we go to the end. Also in this way, we will have greater control of the Jig Saw once the blade comes out of the notch.
- Bevel or Oblique Cuts – Many of the machines o jig sawsThey come with bases that can be adjusted to obtain inclinations from 0º to 45º on both sides of the blade. The base screws should be loosened, and this piece moved slightly until the desired inclination is achieved. Then tighten the screws. It is difficult to make an oblique cut, so if possible, use the lateral guide or fix a guide on the piece.
- Curved cuts: to achieve a curved or circular cut, we use a special accessory that allows the guide to be used as if it were a compass. In this way, we can easily obtain a well-achieved circular cut.
- If we need to start cutting inside the ends of the sheet, a hole must first be made using a drill of sufficient diameter that the jigsaw blade fits loosely, so that the blade is not resting against the material to be cut. . Once we have this opening hole, place the saw and start drilling.
- Having a suitable workbench will optimize our time and improve our quality of work.
Safety Measures in the use of Jig Saws
Although we have already developed an article on the subject in On Machines and Tools, here are some basic recommendations that should be taken into account when using the tool.
- Use the basic safety elements (goggles – safety glasses, chinstrap, loose clothing, closed shoes, etc.)
- Work in clean and orderly environments.
- Check that nothing gets between the piece to be cut and the path of the saw.
- Verify that the cable is never in front of the saw or in the path of it. Make sure you have a long enough cable (to the end of the piece to be pegged). Otherwise use an extension cord or extender.
- Use blades in good condition. Do not use blunt, bent, rusty blades, etc., as they could damage the tool or not achieve a neat job.
- Using the correct blade will save us time and money, and increase our safety.
- Wait until the saw has come to a complete stop once it is turned off. Cutting off the power supply is a good safety measure when you stop using the Jig Saw.
- Make sure the keyhole saw It is provided with a plastic casing that is insulating from any electrical shock that may arise.
- Verify that the material to be drawn is not toxic or harmful to health (example asbestos)
- Keep them tools and machinery out of the reach of children.