set screw sizes

Do you know the basics of screws?

Hardware screws refer to the screw class, just called different, in fact, that is, screws, screws, screws, fasteners, standard parts. The screws of the hardware have the iron, that is, the carbon steel and the stainless steel of the difference.

Generally refers to the standard parts made of metal, which usually include the following 12 types of parts.

1. Bolts.

With the head and screw (with the external thread of the cylinder) two parts of a class of fasteners, they need to cooperate with the nut, used to fix the connection of two parts with a through-hole. This form of connection is called a bolt connection. If the nut is screwed by the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

2. Studs.

There is no head, just a class of fasteners with external threads at either end. When it is connected, one end of it must be screwed into the parts with internally threaded holes, the other end through the parts with through holes, and then screwed onto the nut, even if the two parts are fixed connected in a see the whole. This form of connection is called a pin connection and is also a detachable connection. Mainly used for one of the connected parts thickness is large, requires a compact structure, or due to frequent disassembly, should not be used to bolt the connection occasion.

3. Screws.

It is also a class of fasteners consisting of two parts, the head, and the screw, according to the use it can be divided into three categories: machine screws, fixing screws, and special purpose screws. Machine screws are mainly used for a threaded fixing hole between parts, and a part with a through-hole fixing connection, no need for a nut (this form of connection is called screw connection, it also belongs to the removable connection; can also be used with a nut, for a fastening connection between two parts with a through-hole). Fixing screws are mainly used to fix the relative position of two parts. Special screws are available, for example for lifting parts with lifting rings.

4. Nuts.

With internally threaded holes, the shape is generally shown as a flat hexagonal column, but also a flat square or flat cylindrical column, with bolts, studs, or machine screws, used to fasten the connection of two parts so that it becomes a whole.

5. Self-tapping screws.

Similar to machine screws, but the screw thread is a special thread for self-tapping screws. They are used to fasten two thin metal parts in one piece, which requires a small hole to be drilled in advance, and due to the high hardness of the screw, it can be screwed directly into the hole in the part to form a corresponding internal thread in the part.

6. Wood screws.

This is also similar to machine screws, but the screw thread is a special thread for wood screws that can be screwed directly into a component (or parts) of wood and is used to fasten a metal (or non-metal) part with a through hole in a wood component.

7. washers.

A class of flat circle shaped fasteners. Placed in the bolt, screw or nut support surface and connected parts between the surface, playing a role in increasing the contact surface of the connected parts, reduce the pressure per unit area, and protect the surface of the connected parts from damage; another type of spring washer, can also play a role in preventing loose back nut.

8. fixing ring.

For installation in the machine, the fixture, shaft groove, or hole groove plays a role in preventing the shaft or hole on the parts to move around.

9. pin.

Mainly for parts placement, some can also be used for parts connection, fixed parts, power transmission, or locking other fasteners.

10. rivets.

A type of fastener consisting of two parts, the head, and the nail bar, is used to fasten the connection of two parts (or components) through holes so that it becomes a whole. This form of connection is called a riveted, or riveted, connection. It is a non-removable connection. This is because the rivets on the parts need to be broken to separate two parts that are joined together.

11. Combined parts and subs. connection.

Combination parts are a combination of a class of fasteners provided, such as a certain machine screw (or bolt, since the supply of screws) and flat washers (or spring washers, lock washers) combination of supply; vise connection refers to a special combination bolt, nut, and washer of a class of fasteners provided, such as steel structures with high strength large hex head bolt connection vise.

12. welding nail.

With the nail rod and the nail head (or without nail head) composed of different types of fasteners, with welding methods to connect it fixed in one part (or member) above, in order to then connect with another set of.

Design standard for manufacturing hardware screws

Hardware Screw Manufacturing Design Standards are the standards that must be designed first in all aspects of hardware screw manufacturing and manufacturing. For example, Screw Wire Standards, Screw Mold Standards, Screw Teeth Plate Standards, Screw Machine Adjustment Standards, Screw Product Drawing Standards, Screw Plating Standards hardware, hardware screw tolerance standards. Standards for mechanical properties of screws for hardware, standards for defects in screws for hardware, standards for product testing, standards for methods of marking products, standards for other aspects of marking, and recognition of screw heads for hardware.

Hardware screw technology design and production and other aspects of the standard, in order to make the production of smoothly better, in order to make the hardware screw production more in line with the country-specific national number, in order to better meet the needs of the majority of customers in all aspects. To have the law credible, there are chapters to be found.

The following talk about some hardware screws in all aspects of the specific standards, from the beginning by the screw thread standards, the screw thread standards must comply with the screw specifications to determine the size of the thread standards, how much thread screw thread is needed, what material screw thread is needed. Next is the mold plate standard, which is also based on the specification, type, model, and screw size of the hardware to order the mold. Other aspects are some of the standards set for manufacturing hardware screws, drawing standards for customer-supplied screw samples, tolerance standards for actual manufacturing, head rubbing standards for manufacturing masters, plating standards, and some test standards for making good screws, etc.

Analysis of the causes of rust in hardware screws.

1. plating factory in the plating hardware screws, drying did not dry, resulting in water vapor residue. Or drying in the packaging after condensation has formed. With the result of a chemical reaction, with the result of a bad occurrence, with the result of rusty hardware screws.

2. Long-term storage in humid and wet places, over time, hardware screws slowly corroded, oxidized, resulting in severe rust.

3. When plating hardware screws, the plating is poor, the plating layer is too pry. Resulting in rust.

In a word, analyzing the causes from four aspects. These four directions are 1. storage environment 2. plating type 3. storage method 4. use environment.

Improvement measures.

Storage environment: you need to put the screws of the hardware in a suitable environment, it should not be too wet and humid, it should be ventilated, ventilated, it should not have too much humidity place. There should be a support to put the hardware screws on top and not in contact with the ground.

For the plating type: You should choose a plating color that has a longer salt spray test time. The plating must be well plated and the plating layer must not be too flexible. The storage and storage environment are similar, both cannot be placed in a humid and wet place. Use environment, even similar, can not be placed in salinity, acidity, high salinity, high corrosion, high temperature, high humidity environment.

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