When performing construction work, repairfurniture, as well as for fixing various kinds of home interior items (paintings, shelves, etc.), you can not do without such a necessary thing as a self-tapping screw. There are several types of this fastening tool, but wood screws are perhaps the most commonly used kind. It provides reliable fastening of details from a tree or materials from a tree (DVP, DSP, plywood), and also for fastening of sheets of gypsum cardboard to a wooden basis.
The main feature that distinguishes wood screws from the same for metal is the rarer thread pitch (the slope angle is 45about relative to the top of the profile), respectively, and a smaller number of turns. This is due to the fact that the structure of the tree is not as solid and dense as iron.
What are wood screws?
In its appearance, which depends on the specifics of manufacturing, they can be:
- golden (yellow-passivated);
- white (galvanized);
- black (phosphated).
Независимо от цвета, материалом, служащим для production of self-tapping screws, is high-strength carbon steel. It is subjected to special treatment, which increases the resistance to moisture. After that, the steel is coated either with a thin layer of zinc, or it is treated with a special substance that gives it a yellow color, or is phosphated to improve the material's sliding and ensure a high level of adhesion of the surface of the cap to the finishing material. It should be noted that wood screws are used more often.
- Kernel. The base of the screw, on which there is a thread.
- Golovka. In appearance, there are conical, carob, loop.
- Slot. Depending on the tool used for twisting, there are cross-shaped, straight and hexagonal.
- Tip. Can have a sharp or a drill shape.
В зависимости от того, для крепления каких parts are used self-tapping wood, the size of them can be very different - from 11 to 300 mm in length. The most common self-cutters are 35 mm long and 3.5 mm wide.
Features of using self-tapping screws
- In order for the connection to be sufficiently reliable, it is important to choose the required length of the screw, which must exceed the thickness of the attached part by at least a half times.
- Most self-tapping screws used for bondingparts, do not require pre-drilling holes. However, sometimes you have to deal with hard wood. To avoid damage to the integrity of the slot at the junction, drill a hole in this case. If you use wood screws with a diameter of more than 4 mm, you should also make it to prevent cracking of the wood billet. The hole is drilled to a length of 2/3 of the screw, and the diameter of the drill should be 1-1.5 mm thinner than the width of the screw. Since it is very difficult to find a special drill for wood of the desired diameter, you can use the same, but for metal.
- When using furniture screws(confirmations) drill holes necessarily. In this case, it is necessary to use a special drill having a variable diameter along its length, since such screws closer to the head have a thickening.
