Q:Who knows who invented the screw?

The spirits were invented more than 2,000 years ago, but less than 500 years for fixing things. The first person who describes the spiral is the Greek scientist Archimedes (about 287 BC - 212 BC) The Archimedes spiral is a huge spiral in a wooden cylinder used to The water is raised from one level to another, and the fields are irrigated. Its true inventor may not be Archimedes himself. Maybe he just described something that already existed. Perhaps it was the ancient Egyptian craftsmen who had designed it to use the irrigation on both sides of the river. Archimedes spiral in the ancient society are used to raise water, no one considered to change it into a fixed piece. Archimedes spirals are widely used for water lifting. For example, the Romans used it to drain the mine. In the Middle Ages, carpenters used wooden nails or metal nails to connect furniture and wooden structures. In the 16th century, nail workers began to produce spiral nails, these nails can be more firmly connected things. It was a small step from this nail to the screw. At the end of the eighteenth century, screws were quite popular as fixed parts, because at that time a cheap production method had been found. Screwdriver (chisel) appeared in London around 1780 years. The carpenter found that screwing the screw with a screwdriver was better than a hammer and could fix something better, especially when a fine screw was encountered.

Q:how to Flat washer installation

Flat washers are used on both sides, are required to install.

Q:M4.8 * 25 What does it mean in screw size?

Nominal diameter of 4.8mm, the length of 25.4.8 should be more from the tapping, should not use M said, M generally said machine thread M4.8 is the screw size 25 is the length of the screw diameter 4.8mm, length 25.

Q:This screw ye use, and how to use next to the cover

With the use of electric drill, with the corresponding screw bit on the wall where the need to make a hole, talk about the plastic protrusion into the hole into the hole, then the screw on the.

Q:Inside the hexagonal screws, rather not down, it may be too much screw on the screw too tight has been bad 3 screwdriver screw is too small also one-half of rice grain please help think about ways

First engage in a rust or diesel under the bubble. Then T-type wrench twist. (Own do)

Q:Screws, bolts, screws, what is the difference between the three ah?

The screw is an incorrect call, non-professionals on the threaded parts collectively, in the industry without this call. In the fastener industry, in fact, screws and bolts are not a strict sense of the distinction. However, there are two ways in the industry to distinguish between screws and bolts: 1. According to the structure, the so-called twist structure, refers to the screw / bolt used to put the wrench above the place, that is, In some systems inside, the external pull the structure of the external screw rod-shaped parts are all called the bolt, on the contrary, will pull the structure called screw. This is a more obvious example is the Chinese national standard fasteners, for example, GB5782, GB5783 (a half thread, a full thread), the hexagonal bolts, The Because they are hexagonal structure, so, in the standard name, all called: bolts. 2, according to whether the product has a non-threaded bar features to distinguish. This is also a relatively wide use of a classification method, are generally so distinguish between bolts and screws. That is, if the part of the product other than the head is threaded, this part is called a screw. On the contrary, if, in addition to the thread but also has a light rod and other characteristics, called the bolt

Q:Is it hard to heat the fasteners?

Fasteners are a kind of standard parts, and their requirements are often higher than other standard parts, but heat treatment is better

Q:What is a self-tapping nail? Is it used? What are the characteristics of the shape? What is the difference with ordinary screws?

Self-tapping screws are in the metal or non-metallic materials in the pre-drilling in the self-drilling with a threaded thread with a threaded fastener. Self-tapping screws with high tension, single, unilateral combination of features. Self-tapping screws are used for connection between thin metal plates (steel plates, saw boards, etc.). When connecting, first thread the bottom of the connector, and then screw the tapping screw into the threaded bottom hole of the connected part. As the tapping screw thread surface has a high hardness (≥ 45HRC), can be connected to the threaded bottom hole in the internal thread, thus forming a connection.

Q:How did the scrHow did the screw become round?ew become round?

(1) in the screwdriver head pad things such as double-sided adhesive, non-woven fabrics, etc. If there is no condition, then the paper can be, so you can increase the friction. (2) with a small amount of 502 glue into the screw hole, and then screw into the screw, and so the glue after the solid tip and then use the tip of the screw to pull out the screw (only the screwdriver is not afraid of causing screw teeth). (3) fruit screw cap exposed, you can use the tip of the clamp clamp screw cap after the screw. (4) the general mobile phone screws are metal, the case is plastic, not screw down when the time. You can use the tip of the screw into the screw cap, the metal screws to screw the plastic around the plastic melting, with the tip of the clamp clamp, gently pull out! You can also force down the screws about 1 mm (be careful not to engage in the chassis), you can solve the problem of loose screws. (5) so little the screw is not easy to get, my father had to repair the original bike screw method, with a small electric drill in the middle of the screw to play a not deep hole, and then find an anti-silk tap into the (must Anti-wire tap, it is difficult to find, to go to a large measuring blade cutting shop), you can unscrew the.

Q:how to use Motor washer

What gasket, rubber reduces vibration, metal reduces pressure