Drilling holes in wood
Drilling holes in wood consists in making round cuts or sockets in wood for joinery joints without the use of chisels. At the same time, the holes and slots can be through or so called. blind.
In professional carpentry workshops, a variety of tools are used to drill holes, such as center drills, sitters, twist drills, quill drills and others driven by carpentry cranks. However, we will not deal with these tools, because in home DIY conditions it is difficult to complete these very expensive tools, which are additionally of limited use. For example, it's worth knowing, that a carpentry crank with a so-called ratchet and a precise drill bit holder costs a little less than a two-speed electric drill. So what sense would it make to buy such a crank, if the drill allows us to drill the same holes as the crank (using other drill bits). There is no need to convince anyone about the suitability of the drill for other purposes.
We will supply a home workshop only with the simplest, thus the cheapest hand drill. These will primarily be augers (rys.a), the diameter of which does not exceed 8 mm. They can be used to make smaller holes in the wood, for example, for screws. Another useful type of drill bit are punches (Lynx. b). A punch is simply a sharp spike in diameter 4 mm, embedded in a fairly wide wooden handle. You can make small holes for screws with such a device, Blind holes facilitating drilling larger holes in their axis with an electric drill, or use them for routing (instead of a stylus).
The third very universal type of drill jigs are twist drills (rys.c) for drilling holes in wood, wood-based materials and metals. Of course, twist drills must be driven with a hand or electric drill.
And finally, a very interesting device: saw the so-called. hole saw, powered exclusively by an electric drill, for punching holes in wood with a diameter from 20 to approx 65 mm. It consists of a duralumin body (1) made in the form of a disc, on the surface of which circular grooves are milled (4) forming closed circles with diameters from 20 do 65 mm. The saw body is mounted on a mandrel (2) with a hexagonal cross-section, so that it can be clamped very tightly in the three-jaw chuck of the drill. A hole is drilled in the center of the body, and a simple drill is fixed in it (3), the so-called. saw pilot, which allows it to be centered in the place of the axis of the punched hole. Two radial holes are drilled and threaded in the side surface of the body, and embedded cylindrical screws (5) headless, that pass across the grooves (4). Very important for the correct operation of the saw is also the device that automatically pushes the saw out of the material being cut after releasing the pressure on the drill. This device consists of a sleeve (6) and a spiral spring (7) on the Pilot Drill (3). Of course, not a sleeve, nor the spring are rigidly fixed; can rotate freely on the drill. The most important element of the saw is a set of steel blades (8) rolled up from pieces of steel tape fitted with small pieces, sloping dentition. Each saw comes with as many saw blades, how many circular grooves there are in the saw body. Preparing the saw for work consists in firmly clamping the axis (2) in the three-jaw chuck of the electric drill and pressed into the appropriate groove of the selected saw blade. The blade should be positioned in this way in relation to the body, to make bent cutouts (9) saw blade went on the screws (5). When punching holes, the cutouts will shift like this, that the saw blade is permanently wedged in the groove.
Best to apply I saw a holesaw driving it with a drill mounted on a drilling column. The material to be processed is placed under the saw blade and plunges into the wood by pressing the column lever (in the very exact center of the future hole) pilot drill (3). Then the saw blade, lowered even lower, starts punching a large diameter hole. Do not press too hard on the drill now, in order not to overload its motor and not to overheat the blade. It is better to cut the hole gradually, that is, after each depression of the metal into the wood for about 5 mm loosen the column lever, lift the saw upwards and then continue working. Let's remember, that when the saw blade goes to the other side of the wood, it can fray the edges of the wood. Therefore, it is better to cut holes halfway through the material thickness, and then, after turning the wood over to the other side, finish drilling, obtaining smooth and aesthetic edges of the hole on both sides.
Holesaw, like any mechanical saw, she is very dangerous; all precautions should be taken when using it.