Fastener Basics – Screw classification

According to the structure screw can be divided into following seven types, including slotted screw, cross groove screw, hexagon socket and hexagon pattern screw, swinging rings screw, setting screw, self-tapping screw, and self-tapping locking screw.

1.Slotted Screw

It is used to connect smaller parts. It has pan head screws, cylindrical head screws, semi-countersunk head screws and countersunk head screws. Pan head screw and cylindrical head screw head strength is higher, the bill in the ordinary component connection; The head of the semi-countersunk head screw is curved, and the top of it is slightly exposed after installation, and beautiful and smooth, generally used for instruments or precision machinery; Countersunk screws are used where the nail heads are not allowed to show.

2.Cross Groove Screw

The head of this kind of screw can be embedded in the member, can apply greater torque, higher connection strength, can replace hexagonal bolts. It is often used for joints requiring compact structure and smooth appearance.

3.Hexagon Socket and Hexagon Pattern Screw

Its use function is similar to the slotted screw, can be replaced with each other, but the cross groove ordinary screw groove strength is higher, not easy to screw bald, the appearance is more beautiful. When used, it must be loaded and unloaded with the matching cross - shaped screw.

4.Swinging Rings Screw

Swinging ring screw is a kind of hardware accessories for installation and transportation. The screw must be driven to the position that the supporting surface is closely fitted when using. It is not allowed to use tools to tighten it, and no load perpendicular to the plane of the ring is allowed to act on it.

5.Setting Screw

Setting screws are used to fix the relative positions of the parts. Screw the setting screw into the screw hole of the part to be tightened, and press its end on the surface of another part, that is, fix the former part on the latter part.

Setting screws are usually made of steel or stainless steel materials, and their end shapes are conical, concave, flat, cylindrical and stepped. Cone end or concave end set screw end directly jacking parts, generally used after installation is not often disassembled; The end of the flat end setting screw is smooth, and does not damage the surface of the parts after the top tightening. It is used for the connection where the position needs to be adjusted frequently, and can only transfer small load; Cylindrical end tightening screw used in the need to adjust the fixed position, it can bear large load, but the anti-loosening performance is poor, fixed need to take anti-loosening measures; Step setting screws are suitable for fixing parts with large walls.

6.Self-tapping Screw

When the tapping screw is used in the connected part, the connected part can be made without the thread in advance. Tap the thread directly with the screw when joining. It is often used to join thin metal plates. Its varieties are cone-end tapping screws and flat-end tapping screws.

7.Self-tapping Locking Screw.

Self-tapping locking screw not only has self-tapping function, but also has low torque and high locking performance. The screw thread has a triangular section and the surface of the screw has been hardened to give a higher hardness.

Post time: Dec-30-2022