The screw with a semicircular head is used atthe manufacture of various types of furniture in the construction industry, automotive. This is a reliable method of fastening a wide variety of parts made of wood, metal, plastic.
Types of screws, their classification
Screw - hardware product having the form of a rod witha carving and a head of various forms. Threading is practiced along the entire length of the rod, or only partially. The main difference between screws and bolts is that they are screwed into the part, and the nut is screwed onto the bolt. No additional elements in the form of nuts are required. Used most often for non-through connections. This type of hardware is classified:
- By type of cap.
- By thread.
- By lenght.
The cap of the screw can be made semicircularor flat shape. Manufactured fasteners and with no head. To transmit torque in the screw head, a slot is made (straight, cross-shaped, in the form of an asterisk), knurling or a slot in the end of the rod.
The thread on the rod is small and large in size. It can be cut along the entire length of the screw or only partially.
In length distinguish short, medium and long screws.
Depending on the destination screw with a semicircular head is divided into:
- Fixing hardware.
- Installation hardware.
Fastening screws are used to connect parts with the possibility of further disassembly of fasteners. The set screws are used to fix the parts.
There are two classes of precision manufactured fasteners: A, B. Manufacturing is standardized and the size of hardware by GOST 17473-80.
Such products are made of carbonsteel with corrosion-resistant coating or not galvanized. The most widely electro-galvanized hardware with a strength class of 4.6. A screw with a semicircular head is used in inaccessible places of fastening.
Self-tapping screws with a semicircular head
These hardware products with crossPh Slot or Torx Slot. Used for cutting in the hole of one of the connected parts metric thread. Used to fasten plastic, metal or wood connections.
The diameter of the thread screws vary from size M3 to M8. The pitch of the thread is large - from 0.5 mm to 1.25 mm. The minimum screw length can be from 6 mm for size M3 to 16 mm for size M8.
Furniture screws
Винт мебельный с полукруглой головкой может to be completed with a press washer at the request of the customer, has a cross-shaped slot on the head. The press washer or shoulder makes a single element with a head. The result is an increased surface area at the point of attachment, which significantly reduces the pressure on the material of the product and does not deform it. At the same time, the mount is more durable. Mainly used as fasteners for furniture fittings. The thread is partially cut on the rod.
Cross-shaped slots on the head come in a standard shape (Ph) and an improved shape (Pz).
By the diameter of the thread furniture screws range from size M3 to M8. The diameter of the cap can be from 7.5 mm for size M3 to 19 mm for size M8.
The length of the screw can vary in the range of 6-120 mm.
The screw with a semicircular head and an internal hexagon
Hardware with a semicircular head and a hexagoninternal is used in assembly work for fastening different elements and components of systems. Large sizes of hardware are used in construction and installation works. The internal hexagon in the body of the screw head is essentially a spline.
Screws with a semicircular low cap and a hex key are also available. They are used for screeding furniture elements together with “Erickson” nuts or “Barrel” nuts.
One of the varieties is anti-vandalsecret screw with a semicircular head, a hexagon for the key and a pin in the head for a special bit. They are used as protection against unauthorized access to the junction, dismantling or damage to the fixed equipment. Made from A2 stainless steel. As an option, the release of hardware with a turnkey asterisk is also possible.
There are also screws with a semicircular enlargedcrosshead or slotted flat head, captive screws. Scopes of screws with a semicircular head are very various. It is rather widely used for various types of hardware fasteners.
