Nowadays, the use of mechanical equipment, if you want to be able to operate normally, fasteners are indispensable, but I found a lot of design drawings, and found that almost all designs use hexagon socket screws, whether countersunk or not.
I am very puzzled, why do many devices use hexagon socket screws instead of external hexagon screws? What is so good about it?
Today we will discuss the advantages and disadvantages between the hexagon socket screws and the hexagon socket screws.
01 Outer hexagon screw
The threads on the external hexagonal screws are generally fine-threaded ordinary threads, and the round-threaded ordinary hexagonal external hexagonal screws have good self-pinning properties, and are mainly used for thin-walled parts or occasions subject to impact, vibration or alternating loads.
Generally, external hexagonal screws are partially threaded. Full-threaded external hexagonal screws are mainly used for external hexagonal diameters with short nominal lengths and occasions that require longer threads. Hexagonal screws with holes are used in the occasions that require external hexagonal screws to lock. Hexagon screws with reamed holes can accurately fix the relative position of the connected parts. And can be sheared and squeezed by the force of the die.
The advantage of the outer hexagon is that the pre-tightening contact area is large, and a large pre-tightening force can be used. It is generally used on large equipment, and the price is lower than that of the inner hexagon. The disadvantage is that it occupies a large space and cannot be used in counterbores.
02 Hexagon socket screws
Hexagon socket screws are often used in machinery, and they mainly have the advantages of easy fastening and disassembly, and not easy to slip angle. Allen wrenches generally have a 90° turn. One end is long and the other is short. When screwing with the short side, holding the long side can save a lot of force and tighten the screws better. The long end has a round head (a hexagonal cylinder is similar to a sphere) and a flat head. The round head can be easily slanted in and removed to install some parts that are not convenient for the wrench.
The manufacturing cost of the outer hexagon is much lower than that of the inner hexagon. Its advantage is that the screw head (the force position of the wrench) is thinner than the inner hexagon, and in some places it cannot be replaced by the inner hexagon. In addition, machines with low cost, low power strength, and low precision requirements use fewer hexagon socket screws than external hexagons.
The advantage of the internal hexagon is that it takes up a small space and can be used as a countersunk head. It is generally used in small equipment. The disadvantage is that the pre-tightening contact area is small and too much pre-tightening force cannot be used. The price is a bit more expensive, and there is no full thread beyond a certain length.
So why can hexagon socket screws be seen in many mechanical equipment?
One, bear more load
Hexagon socket bolts have six stress-bearing surfaces, which can be more easily screwed than slotted screws and cross-shaped screws with only two surfaces.
Note: The material of hexagon socket bolts is generally made of stainless steel, carbon steel, alloy steel, and there is basically no difference in the material of other styles of screws. The higher the performance level, the greater the strength. When choosing screws, you must choose strictly according to the requirements of use Screws with suitable performance grades have different grades and different prices.
Two, can be dealt with
The whole nut sinks into the workpiece, which can keep the surface of the workpiece smooth and beautiful.
3. Easy to install
Compared with the outer hexagonal screw, the inner hexagon is suitable for more assembly occasions, especially the narrow ones, so it is very convenient for assembly and maintenance, and it is also convenient for debugging.
Fourth, not easy to disassemble
The tools we usually use are adjustable wrenches, screwdrivers and open wrenches, etc., and special wrenches must be used to remove the hexagon socket bolts. Therefore, it is not easy for ordinary people to disassemble, which is also a benefit.