Self-tapping screws – it is probably one of the most common goods in building products stores. Many of the specialists producing apartment repairs consider them multipurpose and suitable for all types of work. But sometimes there are moments when it is better not to use. From this article, you will learn the advantages and disadvantages of black screws when they can and should be applied, and when you should refuse other.
The term “self-sustaining” is a reduction from the “self-seed screw”. Wide distribution they received in the 60s of the XX century. The main feature is that before screwing them into the material there is no need to pre-drill the hole.
Black is called self-tapping screws coated with special phosphate solutions. For convenience of screwing in a hat there is a slot: it is usually a cross-shaped, but sometimes it is also found. Appointment of selflessness – to fasten various materials. All data settings are reflected in GOST 1145-80 and 27017-86. These standards define the form, material and step of the thread of this fastener for soft and durable materials.
Pros and cons
For black screws, it is absolutely no matter what basis “bite”, be it tree, drywall or plastic: In all these cases, they will cope with the task perfectly. That is, in this regard, they are quite versatile. But Before using them in repair it is worth being ready for some not very pleasant qualities.
In general, black screws have a lot of useful qualities. They are very durable, comfortable in operation, are easily included in soft surfaces, it is inexpensive. But despite all these excellent qualities, there are both bad parties.
Consider the mains.
- The coating is not particularly durable, and if you use such a fastener on the street or in high humidity conditions, it is quite quickly rusty. To prevent corrosion, it is necessary to handle something in addition.
- Do not cope with the bending effort, almost immediately break.
- Designed to fasten designs not very large weight. If they are impressive, self-tapping screws, most likely, will not stand and break.
- With excessive pressure on the hat, you can spoil the slots. Out, then the product will be very difficult: you will have to drill it or climb a new self-tapping screw.
- If the self-sufficient length, then when screwing it, most likely breaks. So you first need to drill a hole.
However, these shortcomings are characteristic of wood and metal.
And in working with other materials, black screws were perfectly shown.
Views and sizes
The key difference of such products is a thread step. Basic types of three.
- The wide distance is typical for products used when working with soft materials. With their help, the tree, plasterboard, plastic, chipboard, fiberboard, MDF.
- Small thread step Used when working with particularly solid wood, hard plastic and metals.
- Multipurpose carving. In such products alternate both ways to cut the turns. They are designed for those cases when it is necessary to fasten materials of different density.
You can also meet Kanenic screws with a drill at the end or with special cutting edges. Still such fasteners are divided by the head. There are quite a lot of them (hidden, semi-crumbbed or protruding), sometimes there are turns (hexagon).
Self-dimensions are listed in the table of the guests developed in the 80s of the last century, and they are still valid. You can meet completely small selfselifers, they are called seeds in the people. But they are quite rare due to low demands.
Based on demand, manufacturers fill the market with the scene. The most widely used products 45, 50, 60, 70 mm long. Assortment of diameters large: from 1.6 to 12mm. But all dictates demand, and in diameter the most running dimensions for metal -3.5 and 3.9, for the rest of the materials – from 3, 5 to 4.8 mm. 4×6 usually apply for drywall.
What differ from yellow?
The most important difference between yellow screws from black – this type of coating. Basically, zinc is used for this purpose. Because of this, they differ in price, but they can be used in any conditions, and they will serve much longer.
How to choose?
When selecting self-seals it is worth paying attention to:
- type of material that is bonded between themselves;
- Thread Pitch: The stronger the material, the less;
- the load that they have to withstand;
- Diameter: If it is excessively large, soft products can crack, and the self-dense layers will not pass;
- View and shape of a hat;
- how the slot is performed;
- manufacturer’s company, because quality is also important.
Each Master itself chooses, what self-draws to use, because much depends on personal preferences.
But black is really very good under certain conditions, most importantly, go with the mind to choose and correctly assess the estimated place of their application.
Detailed information about black screws See in the video below.