Self-tapping weight

Self-tapping screws are of two main types - for metal and for wood. For fastening wooden parts on a self-tapping screw, there is a double threading - two screw grooves running parallel to each other. One such groove is provided on self-tapping screws for metal. Because of this - and not just because of the length and shape of the cap - their weight varies.

As already mentioned, the final mass of the self-tapping screw is influenced by its purpose (metal / wood). The shape of the cap indicates the presence of a press cap, which resembles a regular one, supplemented by a separate pressing washer.

Twice more frequent carving on self-tapping screws for wood allows for a more reliable, better fix, for example, flooring on logs under a massive floor, made of ordinary (including grooved) boards. The tree cracks less than when screwing in a conventional metal screw. However, in case of emergency, both types of screws will replace each other. The fact is that not only the shape and size of the cap, the diameter of the screw and its type are important, but also the length of the products.

The diameter of a self-tapping screw can be measured, for example, using a mechanical micrometer, the contact pads of which crimp the tips on the protrusions of each of the threads.

There are self-tapping screws with beveled threads designed for driving into plastic plugs. The course of the turns of the screws and plugs coincides so that the last turn is tightened with a screwdriver or screwdriver.

Table 1. Plain screws with regular caps (metal-to-metal)

An example of use is for horizontal hangers of a fence, to which a profiled sheet is directly attached.

Table 2. Screws for fixing purely wooden parts and accessories, including black and coarse threads

Table 3. Products that fasten metal components to each other.

There is a possibility of tightening of simple metal structures, there is a pressing washer.

Table 4. Drilling fasteners for fastening metal components to each other

There is a pressing washer - it is part of the product. Ideal for holding profiled sheets on a corner, U-shaped or square (or rectangular) metal profile. Not suitable for a metal profile with a wall thickness of more than 3 mm and for a corrugated board with a thickness of more than 2 mm - the fastening force will be insufficient due to the windage of the entire structure in the wind.

Table 5. "Bedbugs" for fixing thin corrugated board to the same profile

There is an opportunity to drill a hole.

Table 6. Self-tapping screw for fastening sandwich panels to a metal structure, with a pressing washer

Table 7. Drilling screws (suitable for metal-plastic windows)

Take care, for example, when screwing on the cable trunks for the alarm cables. Choosing an unsuitable self-tapping screw in length, or stepping too close to the edge of the glass unit pressed into the frame, you risk breaking the glass.

Table 8. Self-tapping screws for fixing the roofing profiled sheet to the tree

The weight of a self-tapping screw is equal to the quotient of dividing one kilogram of fasteners by the number of copies in it. There is a single, generalized classification that provides for the spread of screws in length from 7 mm to 30 cm and in diameter from 2 to 10 mm. The latter - in terms of diameter - include self-tapping bolts with a hex head, screwed with open-end, adjustable and hex wrenches.

If the scale of work is huge, for example, finishing a new, recently rebuilt 25-storey new building, and the delivery of building materials is carried out with minimization of costs, then, for example, the calculation of the total tonnage delivered in one cargo session will take into account the total weight of the screws. For example, it is necessary to sheathe the walls with plasterboard on all floors - and the estimator calculated that this would take 70 packs of 4x50 screws. Since self-tapping screws "for dumping" in the store can be released in kilograms, each of the packages (for example, 500 pieces in one of them) has its own weight. Accurate, comprehensive calculation is useful when organizing the operational scheduled delivery of consumables to the construction site (or overhaul) of the building. For such a calculation, the above tables of the dependence of the weight of a self-tapping screw on its size are used. They also indicate the number of screws per kilogram.

To calculate the total weight, the user (or object estimator) multiplies the weight of the screw by the total number of screws. For example, if a box of self-tapping screws for drywall (or gypsum fiber) measuring 3.9x19 weighs more than a kilogram, then a hundred such boxes are more than a centner. This is taken into account, for example, if roofing sheet steel, a stack of gypsum fiber board, gypsum, paint and others are simultaneously delivered to the place of work - is it possible to send the required number of packages of self-tapping screws on the same truck for the same flight, or they are delivered on a second flight, for example, in a van "Gazelles" together with metal-plastic windows.