The difference between self-tapping screw sleeve and ordinary wire screw sleeve solutions

To solve the problem of insufficient strength of screw holes and thread holes, previously, it was generally considered to use larger size screws or similar products such as thread sheathing to repair the thread holes that have been damaged, which will increase manufacturing costs and the problem of non-uniform thread hole sizes, seriously affecting the beauty and overall quality of the product. The advent and Application of self-tapping screw sleeves have solved the above problems. They are tapping Inserts for Soft Metal. Also known as Tap-Lok inserts, these inserts cut their threads in soft metals such as aluminum, so there’s no need to tap the hole. Install them into a drilled hole with an installation tool and a ratchet wrench. Installation tools can also be placed in the chuck on a drill press and turned by hand.

The self-tapping screw sleeve does not need to be tapped in advance and can be directly screwed into the specific hole reserved for the base material, for the female thread that has slipped teeth can also use the same screw as the original; economical and beautiful for new products can increase its thread strength, Widely used in automobile industry, rail car industry, munitions industry, shipbuilding industry, household appliances, construction machinery, service machinery, electronic products, engineering plastics, advanced composite furniture and so on.

The main features of self-tapping screw sleeve are:

1. Self-tapping screw sleeve has its tapping ability, and the base material does not need to tap teeth in advance, saving cost.

2. Self-tapping screw sleeve and finished bracelet have a large surface and tensile solid force. Lower strength materials or smaller specifications screws can also be used in product design.

3. For the female thread that has been worn or slipped, the use of self-tapping thread bushing can continue to use the same screw.

4. Self-tapping screw sleeve has strong vibration resistance and can prevent loosening.

5. There is no clearance with the base material, which also has good air tightness if it contains bubbles.

6. Self-tapping screw sleeve installation is simple and rapid, with only one assembly tool, low cost, and almost no defect rate.

7. Self-tapping screw sleeve has a variety of materials, specifications (M2 to M30) to choose from.

What is a self-tapping sleeve?

A self-tapping sleeve (or self-tapping bushing) is a fastener with internal and external bolts and cutting holes or grooves, which is also a new type of fastener with slightly strengthened threads. Self-tapping screw sleeves embedded in plastic, aluminum alloy, cast iron, copper, and other soft materials, can form a higher strength of the internal thread hole, self-tapping screw sleeves can also repair the broken internal thread, self-tapping screw sleeve does not have to tap in advance, can be directly screwed into the specific hole reserved for the mother thread has broken teeth can also use the same screw as the original.

Application of self-tapping screw sleeve:Self-tapping sleeves for light alloys (aluminum, magnesium, zinc, and their alloys), cast iron, brass bronze, thermoset plastics and laminates, and wood.

It is mainly used in automobile engines, transmission components, and other components such as rearview mirrors, heat sinks, shock absorbers, etc. Flange joints of plant equipment, construction equipment, fuel equipment, etc. Household appliances and office equipment; Capacitors, high-current equipment, radio frequency and telecommunications systems, dental equipment.

The use characteristics of self-tapping screw sleeve:

1. Provide strong internal threads on soft substrates to accommodate multiple servicing and disassembly needs.

2. It can effectively repair the damaged internal thread.

3. The self-tapping screw sleeve is used after die casting, injection molding, or other manufacturing processes so that the product structure can be simplified and the output can be increased.

4. The self-tapping sleeve can withstand high loads, so smaller inserts can be used to make the structural design of the product more compact.

Type of self-tapping screw sleeve:

1.302 or 302H series: The 302 series products are the most widely used in all wire screw sleeve products, and its two grooves not only play the role of cutting and slightly inward locking force. Type 302H adds flanges to Type 302, significantly improving the drawing force and torquecantly.

2.303 Series:303 series products are the thin-walled version of the 302 series, mainly used in some plastic or lightweight alloys that cannot have thick walls. In exceptional cases, lubricating oil can be considered during installation.

3, 307/308 or 307H/308H series

The 307 and 308 series are used for difficult-to-cut materials and have a larger wall thickness and shallower but sharper external thread, which uses three holes as the cutting edge. The difference between a 307 and a 308 is the length of the screw sleeve. 307H/308H is the product with a flange added.

4.347/348 series: The 347/348 series products are the thin-walled version of the 307/308 series. They are mainly used in some plastic or light alloys that can not have thick rounds. In exceptional cases, lubricating oil can be considered during installation.

5.317/318 Series: The 317/318 series is specially designed to increase torque and earthquake resistance, and its function is achieved by inserting a pin that complies with the DIN1437 standard.

6.337/338 series:337/338 series products are specially designed to be used when cutting is not allowed to fall into the hole, so the three cutting holes are blind hole designs. For flanges, the code name is 337/338H. The code 357/358 is used if the bottom end is closed.

The difference between a self-tapping screw sleeve and an ordinary thread sleeve (wire screw sleeve):

1. Self-tapping screw sleeve:

● High-strength self-tapping thread

● Only one tool is required for assembly

● Simple and fast device

● Good air tightness and shock resistance

● Original screws or screws of approximate length can still be used

● Automatic assembly can be performed with a ready-made tapping machine

● Repair can be performed in almost any location or small space

● High surface hardness, no secondary tooth failure

● Low total device cost

2. Thread sheath (wire screw sleeve):

● Must use particular time off-mark tap to tap thread

● Must be used with a variety of special tools

● The device program is complicated and slow

● No function or not significant

● Screw length is limited by sheath length

● Need to design more complex machinery

● The source is not easy to perform repair work

Installation method of self-tapping screw sleeve:

1. When the number of installations is small, the simple installation method can be adopted, which is to take the corresponding specification bolt + nut method, as shown in the following figure, the self-tapping screw sleeve is fixed on the corresponding Type of screw, and the same Type of nut is fixed, so that the three become whole, screw the screw sleeve into the bottom hole with a wrench, and then the screw can be withdrawn.

2. When the number of installations is large, use a dedicated screw sleeve installation tool. For details, see the following figure. In the figure below, the end of the tool is a hexagonal head, which can be connected to a manual tapping wrench or an electric or pneumatic tool.

Self-tapping sleeve installation precautions:

1. refer to the drilling size specifications and pre-drilling processing for different processing materials. When the hardness of the corresponding material is high, please slightly increase the bottom hole in the drilling range.

2. The slotted end will completely install the self-tapping screw sleeve into the front end of the tool and contact the workpiece vertically. Please align the bottom hole when loading (1P~2P) and never tilt. Do not reverse the tool when you find a tilt; re-adjust it before using it. After entering 1/3~1/2, you can not come back again. In addition, please do not reverse-rotate the tool. Otherwise, it will cause product failure.

Please get in touch with me if you want high-quality tapping inserts for soft metal and fasteners or technical support for structural design. Thanks.Email:adelajonly@gmail.com

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