How to use screws

This article will address the screws, simply because the practice of DIY they are used very often. Mainly because they screw up mostly in the tree. From the tree made a lot of items that must sometimes be repaired. Besides the wooden parts easier to handle than metal, so the tree must often work in the construction of something from scratch. This article will focus on screws, simply because in practice they are masters of the home used very often. Mainly because they screw up mostly in the tree. From the tree made a lot of items that must sometimes be repaired. Besides the wooden parts easier to handle than metal, so the tree must often work in the construction of something from scratch. Saw all the screws, but use them correctly are able to very few. It is better to buy imported screws, which are often called self-tapping screws. (Frankly, I do not quite understand what is different from the self-tapping screws.) Import screws stronger and much better, although they are somewhat expensive. And when you consider that the thread on them to roll smooth, and from domestic - shaggy (and therefore hard to wrap), it becomes clear that domestic screws everything has been done to make it convenient to break their slot. First about how to arrange the screw. In general, it has a cap, unthreaded rod and its extension to the thread. The screw is always used to bond at least two parts. So this thread should all reside in one piece, then there is this part must have a thickness of not less than L (the figure). And other details must not be thicker than l (again, a drawing). If you attach, say, a thin metal plate to a wooden board, then the length l can be quite small, that is, all the screws (except for hats, of course) will be threaded. If you will screw the screw threaded part in two different parts, then between them necessarily form a gap, and pull it fails. One of the parts must necessarily fall on the smooth part of the screw. Now about the different hats. Here the picture shows the different types of cap screws, blue line shows where the surface of the material must pass, which is screwed a screw. Slots conditionally not shown. The first figure shows a screw with flat head, the most common. Used where the surface should be smooth. Hat dug into the material, in a pre-made countersink. The second type - a lentil head protruding above the surface of the material, but looking better than flat. The third type - with a head like a bolt, it is plain, but powerful. On this head does not happen grooves, wrapped screw wrench. Finally, the fourth type - a semicircular cap. Used when fixing the fine details of when the countersink do nowhere. Countersink is a special drill, which makes a conical recess. Angle "collapse" of the cone - 90o, on the usual drill large diameter is not suitable, he corresponding angle of 70o. Since not countersunk drill deep holes, blunts it a little, and there are no strict requirements for quality sharpening. Therefore, we can peretochit drill of suitable diameter to countersink. Slots on the cap are very different. The most simple - a straight slot, just a notch, twist the screw flat-blade screwdriver. The most common - a cruciform, a screwdriver like a cone with four slots, and slot on the cap has the shape of a cross. There is also an enhanced cross-slot, it looks like a cross overlaid with the four-beam star, rotated 45o with respect to the cross. Some screw slot in the form of an internal hex, nice looking, but requires very precise and therefore expensive screwdriver. Most convenient to work with cross-shaped or reinforced Phillips, because the screwdriver does not slip sideways and you can tighten the screw even blindly, without seeing it. But if a screw or screwdriver is not very high quality, with Phillips you just namuchaetes, in this case, better take the screws with straight slots. Sometimes with screws (and sometimes sold separately) includes decorative plastic cap. It is inserted into the slot wrapped in place screws, concealing it. Less commonly, metal plugs, threaded stem, and the response thread cut by the end of the screw. But in any case screws with plugs expensive. Now let's talk about how to properly wrap up the screw. How to choose the length of the screw and its threaded part, above. Still need to find the diameter of holes drilled for screws. Tochnee, drilled two holes in two different thickness of drills, plus (possibly) countersink. One, a large diameter (D) wants this to go just entered without the efforts of the threaded screw and its smooth part of a hat. A second diameter should be equal to the diameter of a thin rod screw (d). As has been said, screwing a screw can only be in one piece through another piece screw should pass freely. If you have material that you're going to screw the screws, soft, or very short screws, take a fine drill bit smaller than d, the diameter (or even instead get a shot with an awl). In the case of solid material and (or) a long thin screw auger may take a little thicker. There are special drill all the screw just below, they are graded. You add two mating screw parts, and for one drill a hole once the desired shape, so even countersunk. Negative - must be a bit under each separate size of screws. And now a few tips if the connection is not too responsible, we can take a screw thread along the entire length, and assume part of the screw under the cap is smooth and thick. Of course, it's not quite right, but not fatal. Naturally, the drill hole diameter D is still needed. The screw is very useful to fix with glue. Clay at tightening the screw will act as a lubricant, and then will securely hold the screw from unscrewing under variable load. Turn the screws must be precisely suited to the slot with a screwdriver, because otherwise you will either mess up the screw, not dovernuv it through, or destroying a screwdriver. Verify compliance with a screwdriver slot is simple. Push a piece of clay into a screw slot, and then paste the screwdriver blade. If all the clay squeezed out - screwdriver fits. Usually in practice, DIY missing three straight with a screwdriver tip and three cruciform. Short is always worse than a long screwdriver. Human hand is so arranged that when trying to turn the screwdriver around its axis turns more and tilt of this axis. The longer the screwdriver, the smaller the slope, and more reliable contact with a screwdriver, screw. Each stall with a screwdriver slot pulls out a piece of metal or of a screw, or of a screwdriver, and you or can not screw the screws, or throw a screwdriver through the dozens of wrapped screws. It is always best to screw a few small screws than one major. The whole construction will be safer, if only because the load is evenly distributed. You can draw an analogy with a broom and a thick stick - if you stick a twig or a crack, to break it will be easy, and a few cracked twigs in a broom almost not reduce its overall strength. Pull the screw along its axis is easier than to move him sideways. This must be taken into account when planning a link on the screws. www.rosmetiz.ru