Standard sizes
The parameters that determine the size of the screw are diameter and length. The diameter of the product is determined by the diameter of the thread circle. The main dimensions of all screws produced are standardized by the following documents:
- GOST 114-80, GOST 1145-80, GOST 1146-80, GOST 11473-75;
- DIN 7998;
- ANSI B18.6.1-1981.
The length and diameter of the screw are selected based on the expected load on the connection
In addition, when choosing the diameter of the product, you should pay attention to the recommendations of the manufacturer of the dowels, which are indicated on the packaging. The head of the screw after screwing into the dowel should protrude a short distance
Another factor is the thread and its pitch. It is worth remembering that the M8 thread, for example, can have a different pitch.
Let's consider the most common types of screws and their typical sizes.
With a semicircular head
They are used when working with wood, plywood or chipboard. The length varies from 10 to 130 mm, the diameter is from 1.6 to 20 mm.
The size range looks like this (in millimeters):
- 1.6x10, 1.6x13;
- 2x13, 2x16, 2.5x16, 2.5x20;
- 3x20, 3x25, 3.5x25, 3.5x30;
- 4x30;
- 5x35, 5x40;
- 6x50, 6x80;
- 8x60, 8x80.
Crutch (ring, half ring)
They are used for laying electrical circuits, fastening construction equipment, equipping sports halls and similar facilities.
The standard size can be as follows (in millimeters):
- 3x10x20.8, 3x30x40.8, 3.5x40x53.6;
- 4x15x29, 4x25x39, 4x50x70, 4x70x90;
- 5x30x51.6, 5x50x71.6, 5x70x93.6;
- 6x40x67.6, 6x70x97.6.
Plumbing
A distinctive feature of this type is the hexagonal head. It is used for fixing various sanitary ware (for example, toilets) on various bases.
Standard size: 10x100, 10x110, 10x120, 10x130, 10x140, 10x150, 10x160, 10x180, 10x200, 10x220 mm.
Self-tapping screws
Some of the most common options. It is used in a wide range of works. Size (in millimeters):
- 3x10, 3x12, 3x16, 3x20, 3x25, 3x30, 3x40, 3.5x10, 3.5x12, 3.5x16, 3.5x20, 3.5x25, 3.5x30, 3.5x35, 3.5x40, 3.5x45, 3.5x50;
- 4x12, 4x13, 4x16, 4x20, 4x25, 4x30, 4x35, 4x40, 4x45, 4x50, 4x60, 4x70, 4.5x16, 4.5x20, 4.5x25, 4.5x30, 4.5x35, 4.5x40, 4.5x45, 4.5x50, 4.5x60 , 4.5x70, 4.5x80;
- 5x16, 5x20, 5x25, 5x30, 5x35, 5x40, 5x45, 5x50, 5x60, 5x70, 5x80, 5x90;
- 6x30, 6x40, 6x4, 6x50, 6x60, 6x70, 6x80, 6x90, 6x100, 6x120, 6x140, 6x160, 8x50.
How to choose?
Using the information provided, the following instructions should be followed when choosing the necessary screws:
- determine what work requires screws and what materials will be used (for example, cable installation, furniture assembly);
- calculate the size of the surfaces to be connected;
- find out in what conditions the proposed compounds or materials are located (humidity, high temperatures, the presence of water).
Given these points, it will be possible to determine the length and type of fastener required, its coating, thread and pitch. This will select the optimal screws for the specific task.
An overview of the screw sizes in the video below.