Self tapping screw introduction and specification

2012-12-25 17:13 Source:未知 Writer: admin

Individual refers to the pointed, coarse, hard wood screws, but also for the aluminum alloy, plastic. For metal hole screw thread of a special self-tapping screws are called silk attack.

Self tapping screw used for non metal or soft metal, do not have to fight low and tap holes; self-tapping screws is pointed, such ability " tapping "; ordinary screws are truncated, the same thickness.

Self tapping screw is said: drill hole chipless tapping hole, with screws and individual difference, head is a sharp contrast, pitch, and chipless screw tap is a bit like, can not be tapping directly screwed out of metal and plastic, usually using this method.

Self tapping screw, the screw nut is not.

It can be consolidated information on, by its own thread, will be consolidation "attack - drill, squeezing, pressing " a corresponding threaded, so closely with each other.

Offset: ( from Tongji University ) self tapping screw is a screw with drill, through a dedicated electric tool construction, drilling, tapping, fixation, locking a realization. Self tapping screw used for some of the more important pieces of sheet metal connection and fixation, such as steel and color steel plate convergence, color steel plate with purlins, wall beam convergence, the penetration ability of individual does not exceed 6mm, the maximum not exceeding 12mm. Self tapping screws are often exposed to outdoor, itself has a strong corrosion resistance ability; the rubber sealing ring can protect the screws is impermeable and have good corrosion resistance.

Tapping screws with screw diameter series, usually per inch length of thread number and length of screw three parameters to describe. Screw diameter series 10 level and 12 level two, which corresponds to the screw diameter were 4.87mm and 5.43mm; every inch length of thread number 14, 16, 24 and three levels, each inch length of thread number, its self drilling can be stronger.

In 1 ( Evolution ):

Since 1914, self-tapping screws beginning commercialization. First design - important from wood screws - of carburizing steel tail cone type A thread forming screws. Prior important use is used in air conditioning system catheter tin joint, which is also called metal screws. After more than 80 years of development, is divided into four period - thread forming, thread cutting, thread rolling and self drilling.

Thread forming tapping screws ( Thread Forming Tapping Screws ) -- directly by the iron screw out, thread forming tapping screw used to be after drilling, the screw is screwed into the hole, strong extrusion with female thread, which female thread status information will be pushed to the male, this is thread forming tapping screw can only be applied to thin with plasticity of materials, and carry out; thread cutting tapping screws ( Thread Cutting Tapping Screws ) -- in the threaded end cutting out a or a plurality of the cutting port, enabling the rotation into pre-drilled holes, using screw tail and tooth part in a similar screw the method of cutting out the attack with a female thread. It can be used on the plate, or a frangible comparison is not easy to shape information,.

Thread forming tapping screws ( Thread Rolling Tapping Screws ), triangular teeth screws, also known as Type TT ( Type Tai was still patent) is based on the principle of forming screw tap out, thread forming tapping screws with a special design of the screw thread and end in intermittent pressure to roll to fit into the female thread . At the same time, Kong Sizhou's data can more easily make up a self-tapping screw thread and tooth bottom space, because the friction of a thread forming tapping screws for small, and thus can be used in a thick material, rotating the required torque to better grasp, and after the combination of higher strength. Thread rolling tapping screws and its engineering specification definition than forming or cutting tapping screws in the data, heat treatment, the strength of the definition is more and more obvious, the thread forming tapping screws into the real " structure with fastener. "

Self-drilling and tapping screws ( Self Drilling Tapping Screws ) - also known as Tec, in the assembly of self-tapping screws of all process, the consumption cost is pre-drilled preparation self-tapping screws used, must first drilling and aperture must also limit without pre-drilled holes in some areas to save the cost. Is the set of drilling, tapping, onto a work of drilling tail tapping screw drill tail screw surface hardness and core hardness than the individual self tapping screws a little higher, this is because the drill tail screw has a drilling operation, the drill tail screw need through experiment, to test the screw in regular time drilling attack thread. The four important self tapping screw design and development process, and another two for the special design of screw thread, a first for; high-low thread tapping screws ( High - Low Tapping Screws ) - used in plastic or other low density data. Double screw thread design, high screw ( tooth part with larger outer diameter ) with flat more sharp thread angle of 30 degrees of the screw type. The lower threaded ( tooth of smaller diameter ) with a 60 degrees angle of thread, thread tooth high as long as half high . High thread combination design reduces the rotational torque, reformed the pull out strength, substantially reduces the risk of portfolio workpiece break another used in the construction industry ( Drywall ) dry wall assembly use., with such threads design of self-tapping screw is suitable for plastic, plate and wood.

Another kind is; double thread self drilling tail horn head tapping screws ( Twin Lead Self Drilling Point Tapping Screws ) -- when assembled can screw into the dry wall, in the iron and steel teeth from the drill hole and tap with the female thread at the horn head with recessed under the surface can be screwed in time as for the damage to the wallpaper or plaster surface. Most of the self-tapping screws belong to the commercial use, such as when the self-tapping screws to screw combination ( SEMS ) supply, can supply the more strict service. While the screw thread with coarse and fine special designer is focusing on the anti-loosing after assembly.

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