What is the difference between non-standard screws and self-tapping screws?

Update:10 Dec 2020
Summary:

Non-standard screws generally refer to pointed, coarse- […]

Non-standard screws generally refer to pointed, coarse-toothed, hard-textured wood screws, and they are also used for aluminum alloys and plastics. A special self-tapping screw used for threading metal holes is called a tap. Stainless steel flange self-tapping screws are used for non-metal or softer metals, without drilling and tapping; steel wire self-tapping screws are pointed, so that they can be "self-tapping"; ordinary screws are flat-headed and the thickness is the same. The screws used are different from ordinary ones. The head is pointed and the pitch is relatively large. The LED tube is a bit like a chipless tap, and it can be directly screwed in without tapping. This method is usually used for metal and plastic. Angle seat valve self-tapping screws are screws without nuts. It can be on the material to be consolidated, the explosion-proof motor relies on its own threads to "tap-drill, squeeze, and press" the consolidated body to produce corresponding threads to make them closely match each other. Steel wire self-tapping screw is a kind of screw with a drill bit, which can be drilled, tapped, fixed and locked at one time through special electric tools.

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Characteristics of stainless steel screws:

1. Drilling and tapping, locking can be completed in one time, strong bonding force.  
2. Save construction time and improve work efficiency.

Be applicable:

1. General angle steel, channel steel, iron plate and other metal materials are combined and installed.  
2. Assembling projects for automobile trunks, container boxes, shipbuilding, refrigeration equipment, etc.
3. Stainless steel plate, metal steel plate, galvanized steel plate, engineering installation.  
4. Metal curtain wall, metal light partition, etc. indoor and outdoor installation.