Carbon steel M5 M8 Thumb Screw Black finishing Class8. 8 Grade 8.8 Iron Spade

Product Specification

Carbon steel M5 M8 Thumb Screw Black finishing Class8. 8 Grade 8.8 Iron Spade Head Thumb Screw
 
Product Description:

Hand screws (sometimes written thumbscrews) are multi-purpose fasteners designed to be tightened and loosened manually without the need for tools such as screwdrivers or wrenches for installation. They have a wide range of useful applications, especially in parts, materials and structures that do not easily support the use of hand or power tools. This is often due to space constraints.

Hand screws and thumb bolts may also be useful solutions in situations where you may need to remove components or panels on a regular basis. They can make tasks such as maintenance or cleaning quicker and easier than using mechanical screws, bolts or rivets that are fully tightened with a driver.

Various types of fasteners and fixings may fall under the broad definition of hand screws. True hand screws or bolts can be distinguished from standard bolts or rivets by their large heads, which provide an easier grip. They have knurled edges around the head to further improve friction and grip when turned by hand. They may have a screwdriver slot in the head if desired. Washers are usually not required to use this type of fastener.

Knurled Hand Screws

Most hand screws are usually made of steel, brass, plastic, resin or a combination of these materials.

Brass Knurled Head Hand Screws
Brass knurled head hand screws are usually plated with nickel or a similar wear-resistant material for better corrosion resistance and a cleaner chrome-plated look.

Plastic Hand Screws
Plastic hand screws - usually nylon - are ideal for a variety of low-cost, non-structural applications. They are especially cost-effective if you only need screws that are effective, lightweight, strong, corrosion-resistant, insulated and easy to tighten or loosen.

Steel Hand Screws
Steel hand screws are one of the more durable and reliable material types in this category. They offer excellent rigidity and positional accuracy, and stainless steel is also an option where the material must maintain a flawless appearance over a longer period of time.

Resin is commonly used for head moulding on thumb knobs, whether they are the traditional star head type or flat knob screws with moulded shoulder wings for easier grip between thumb and forefinger. These are sometimes called quarter-turn panel fasteners. The threaded screws themselves can also be moulded from plastic resin or made from metal and attached separately.

Hand Screw Sizes
Most hand screws usually come in long or very short lengths, depending on the application they are needed for. In order to choose a better hand screw, it is important to take into account some characteristics such as length, diameter and thread size.

Small hand screws may only be less than 4mm long from the shoulder to the end of the thread, whereas long hand screws usually extend to about 25-30mm (1 inch) or even longer. For most everyday fastening operations, it is rare to find very long hand screws. This often means that the product needs to be stronger (smaller deflection range) and have greater tensile strength than these relatively small fasteners provide.

The length of a hand screw is almost always measured in millimetres (mm) and measured from the underside of the head or shoulder to the opposite (flat) end of the threaded portion.

What is the role of Thumb screws?
Thumb screws can be used in a variety of tasks and assemblies. Their primary use is to fasten panels, wiring, covers, safety covers, battery compartments, and any part or assembly that may need to be removed and reinstalled frequently. Cheap hand screws, thumbscrews and thumbscrews are widely available online and are usually sold individually or in bulk.
It is also common to find pre-installed hand screws on a variety of consumer electronics and household appliances. Whilst most are used in some form of plastic or metal assembly, it is not uncommon to see hand screws in specific types of wooden assemblies, due to the specific type of construction, mounting or action they perform making them a suitable choice. Larger sized models are also used in a variety of industrial applications.

Applications:

Carbon Steel
Carbon steel, also known as carbon steel, is an iron-carbon alloy with a carbon content of Wc less than 2%. In addition to carbon, carbon steel generally contains a small amount of silicon, manganese, sulfur, phosphorus.
According to the use of carbon steel can be divided into carbon structural steel, carbon tool steel and free cutting structural steel three categories. Carbon structural steel can be divided into two types of structural steel and machine structural steel.
According to the carbon content of carbon steel can be divided into low carbon steel (Wc ≤ 0.25%), carbon steel (Wc 0.25% 0.6%) and high carbon steel (Wc> 0.6%) according to the phosphorus, sulphur content can be divided into ordinary carbon steel (phosphorus, sulphur, higher), high-quality carbon steel (phosphorus, sulphur, lower) and advanced high-quality steel (phosphorus, sulphur, lower).
The higher the carbon content in general carbon steel, the higher the hardness, the higher the strength, but the plasticity is reduced.

Translated with www.DeepL.com/Translator (free version)

Compared with ordinary steels, special steels have higher strength and toughness, physical properties, chemical properties, biocompatibility and process properties.

Compared with ordinary steel, special steel has high purity, high uniformity, ultra-fine organisation and high precision:
(1) High purity. Targeted reduction of gas, inclusions (including low melting point metal inclusions) in the steel content. The purity of steel to a certain limit, not only can significantly improve the original performance of steel, but also give the steel with new properties. For example, the oxygen content in bearing steel from 30 × 10-6 reduced to 5 × 10-6, the bearing life increased by 30 times. General austenitic stainless steel in the phosphorus reduced to 3 × 10-6 is immune to stress corrosion. the end of the twentieth century, large-scale production of steel can be achieved by the purity level (10) for: hydrogen ≤ 1, oxygen ≤ 5, carbon ≤ 10, sulfur ≤ 10, nitrogen ≤ 15, phosphorus ≤ 25.
(2) high uniformity. Steel composition segregation leads to steel organisation, uneven properties, which is one of the important reasons for the early failure of steel parts and steel performance potential is difficult to give full play to. Modern production processes should make the uniformity of steel to achieve: car gear steel hardenability band fluctuations of ± 3 HRC; the precise level of control of alloying elements for carbon, nickel, molybdenum content of ≤ ± 0.01%, manganese and chromium content of ≤ ± 0.02%; bearing steel quenched grain size of spherical and size fluctuations of 0.8 ± 0.2 μm; resistance to laminar tearing of the longitudinal direction of the steel (z to the steel), the lateral direction of the thickness of the mechanical properties, especially plastic, toughness requirements largely. In particular, the plasticity and toughness requirements are roughly equivalent.
(3) Ultrafine organisation. Ultrafine organisation strengthening is the only strengthening mechanism to increase the strength of steel without reducing the toughness or a slight increase in toughness. For example, high-strength stainless steel AFC77 grain refinement from 60μm to 2.3μm, the fracture toughness KIC from 100 to 220MPa-m. Nuclear reactor pressure vessel steel plate for coarse crystal, its irradiation embrittlement temperature range of 150 ~ 250 ℃ and fine grain steel down to 50 ~ 70 ℃. Bearing steel in the carbide size fine to ≤ 0.5μm, the bearing life is greatly improved.
(4) high precision. Special steel to have good surface quality and narrow dimensional tolerances. The accuracy of hot rolled steel bar has reached ± 0.1mm, hot rolled coil thickness tolerance of ± 0.015 ~ 0.05mm, while the thickness tolerance of cold rolled coil has reached ± 0.003mm.

Oxidation temperature and time for different steel parts:

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