Dimensions Of Self-tapping Screws: Table. How To Determine The Size Of A Self-tapping Screw For Socket Boxes? Universal Sizes. What Are They Like?

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-18 12:09

The range of fasteners presented in modern hardware stores is amazing. A huge number of products of all kinds of shapes, colors and sizes for various purposes, which are sold both in bulk bags or boxes, and individually. They were no exception and self-tapping screws , which have long ago pushed from the shelves and even practically replaced the nails familiar to old repairs.

But in order not to get confused and choose the right fastener detail, it is worth knowing what each of them is intended for, from the smallest to massive metal screws with plastic dowels included.

What are they?

As with any fastener, the dimensions of a self-tapping screw are their diameter and length … In order to prevent the buyer from purchasing different products for the same marking when buying in different stores, all self-tapping screws must comply with certain dimensional standards. For European manufacturers, these are:

• DIN - German standard;
• ISO is an international standard;
• GOST is a domestic standard.

In many ways, these three standards coincide, although they have their own nuances . The manufacturer in the description of the goods is obliged to indicate the characteristics in accordance with one of them. And in order to make it easier to standardize self-tapping screws by standard size, they are divided into several types.

By wood

The main difference between such screws is enough coarse thread … This is explained by the low density and hardness of wood, which makes it possible to produce thinner and longer hardware (from the words "metal products"). Their length ranges from 11 to 200 mm, and their diameter ranges from 2.5 to 6 mm. The harder the wood, the larger the size of the fastener has to be selected . Most often, self-tapping screws for woodwork are called universal. For home repairs, the cheapest self-tapping screws with plastic dowels are enough to fix baseboards, socket boxes or hang a shelf on the wall.

In cases where the material is too dense, a hole is drilled before fastening to the self-tapping screw. In order not to spoil the structure, you should carefully select the drill diameter. This can be done using a small table.

Self-tapping screw diameter	Drill diameter
4.0 mm	2.5-3.0 mm
4.5mm	3.0-3.5mm
5.0 mm	3.5-4.0 mm
6.0 mm	4.5mm

For metal

Self-tapping screws for working with metal are somewhat different from those intended for wooden structures. Their length ranges from only 9.5 to 75 mm, and their diameter starts from 3.5 mm and ends already at 4.2 mm.

The smallest self-tapping screws, which are usually used to fasten plasterboard profiles, are often called "seeds" by builders.

With press washer

Such elements can be called universal, because they are used for fixing wood, metal, plastic, siding and many other materials … Their distinctive feature is a large hat, which is called a press washer . With its help, it turns out to press the fastened structure more tightly, without using additional washers. Their length is from 13 to 64 mm, and their diameter is always 4.2 mm.

Roofing

Self-tapping screws, which fasten strips of profiled sheet, metal tiles and other types of roofing, have a length from 19 to 100 mm, and a rod diameter - from 4, 8 to 6, 3 mm . Instead of a regular cap, they have a large washer with a rubber gasket, which does not allow water to pass through, which is very important when installing a roof. However, they are often used for fastening other structures, for example, a fence made of a corrugated sheet or a metal garage door frame.

Furniture

Such self-tapping screws are called " Confirmations ", they are used in the assembly of various furniture. Their length is from 40 to 70 mm, and their diameter is from 4, 72 to 6, 05 mm. Such self-tapping screws always require preliminary drilling of the marked holes with a special confirmation drill; screw them with a special hexagon, and not with an ordinary screwdriver.

Capercaillie

Such fasteners are used for the installation of heavy structures, where high strength and reliability are especially needed, for example, in the construction of interfloor floors .… Their length is usually 40 mm, and the diameter starts at 6 and ends at 10 mm. The hexagonal head is tightened with an ordinary wrench or a special attachment for a screwdriver.

To further increase the reliability of such an attachment, a plastic dowel is used.

How to determine?

It is quite difficult to learn all the standard sizes of self-tapping screws by tooth, and besides, there is no need for this. Furniture or other interior items are often sold already with suitable fasteners, and in order to find out which self-tapping screw to buy for a particular building material, just look at its carvings.

The following options are distinguished by the type of thread

Thread pitch	Appointment
Average	Universal. Suitable for metal, wood, asbestos, plastic, plaster and other materials.
Frequent (or even double entry)	Perfect for fastening metal profiles no thicker than 9 mm. They hold perfectly without dowels, but require preliminary drilling.
Rare	For materials of high softness: asbestos, gypsum, soft wood, plastic. No dowels required.
Herringbone	For brick and reinforced concrete. Requires a dowel.
Notched	For brick and reinforced concrete. No dowels required.
Asymmetrical	For assembling furniture from chipboard, plywood, wood. Requires pre-drilling.

In general, to select the correct size of a self-tapping screw, you must adhere to a few simple rules

1. The length of the hardware should be such that it can be sewn through the attached element and anchored in the base.
2. Particular attention should be paid to the length of the self-tapping screw when choosing fasteners for wooden structures. The fastening should go through the part and enter the workpiece no more than 1/3 of its thickness if it is not fixed with corners, and 1/4 if it is fixed.
3. The price of a self-tapping screw directly depends on its length, therefore, the use of fasteners longer than necessary is irrational from the point of view of economy.
4. The heavier the self-tapping screw, the heavier the total weight of the structure. You can ignore this in a single use, but in certain cases the builder can use up to several hundred thousand self-tapping screws per structure, and in this case, their total weight will be significant.

In order to choose a dowel for a self-tapping screw, you can contact the store seller or use the following plate

Dowel	Self-tapping screw
	2, 5-3
	3, 5-4
	4, 5-5
10
12
14	10

How to choose?

It is not enough just to determine the correct dimensions of the required fasteners - on the market itself or in the online store it is necessary to choose a high-quality self-tapping screw from the whole variety of options . To do this, it is enough to carefully examine the proposed product.

If it is of high quality, it will meet the following criteria

1. One color spectrum the whole party. The color of all products, even packaged in packages, should not differ even in shade. If the color is different, it indicates different processing and manufacturing conditions.
2. One the size … Products from the same batch should not have differences in dimensions visible to the human eye.
3. One thread … The distance between adjacent threads of high-quality hardware is always the same.
4. One slot … The recess in the head for the screwdriver on all self-tapping screws in the batch must be of the same size and depth.
5. Marking … All factory products are marked in the form of capital letters of the Latin alphabet. If it is not there, it is better not to buy such a product.

In the event that the fastener selected in the store meets all the above rules, it can be safely used when installing a structure of any complexity. After all, a quality product will make even the most exhausting and protracted repairs easier.