How do you use fasteners correctly? Solutions for installation, removal, maintenance, and more

How do you use fasteners correctly? Solutions for installation, removal, maintenance, and more

Fasteners are a common mechanical component that holds two or more parts together. They must be installed, disassembled, maintained, and serviced correctly to ensure their safety and effectiveness.

1. Before installing fasteners, ensure you have all the necessary tools and materials, such as screwdrivers, wrenches, hammers, bolts, nuts, washers, and seals.

2. Install fasteners properly according to the type of fastener and installation requirements.

3. Fasteners should be installed in the exact position and ensure that they can withstand the required loads and pressures.

4. After installing fasteners, they should be checked for looseness, slipping, or other irregularities and repaired promptly.

5. Appropriate tools and equipment, such as screwdrivers, wrenches, and hammers, should be used when removing fasteners. The type of fasteners and installation requirements should be determined before the disassembling operation.

6. After removing fasteners, clean and inspect them for damage or other irregularities. If fasteners need to be replaced, use the same type and size and ensure they can withstand the required loads and pressures.

7. Safety should be observed when using fasteners. When installing and removing fasteners, take protective measures, such as wearing gloves, safety glasses, and protective clothing.

8. Regularly service and maintain fasteners. This can include cleaning, lubricating, replacing damaged fasteners, etc.

9. A professional should perform mA professional should perform maintenance and care of fasteners to ensure their safety and effectiveness.

10. If fasteners need to be used with other systems or equipment, you should understand the match between them and make sure they work together.

When using fasteners, the following matters should be noted:

1. Fasteners should be stored in a dry, well-ventilated environment to avoid moisture, rust, and other damage.

2. To extend their service life, Fasteners should be mixed with appropriate lubricants, rust inhibitors, etc.

3. When using fasteners, proper procedures should be followed to avoid damage to fasteners or other equipment.

4. When used, Fasteners should follow the manufacturer's instructions or relevant safety standards.

Classification of fasteners, identification and inspection of threads, material requirements, heat treatment requirements and mechanical property requirements of bolts, screws and studs, types and construction of steel bolts.

Classification of fasteners

1. What is a fastener?

Fasteners are two or more parts (or components) tightly connected to become a whole when used in a class of mechanical parts of the general term. The market is also known as standard parts.

2. Usually including some kinds of fasteners:

Bolts, studs, screws, Hexagonal nuts, self-tapping screws, wood screws, washers, retaining rings, pins, rivets, combinations and connectors, welding screws.

(1) Bolt: by the head and screw (with external threads of the cylinder), two parts of a class of fasteners need to cooperate with the nut, used to fasten the connection of two parts with a through hole. This form of connection is called bolt connection. If the nut from the bolt spins down, it can separate the two parts, so the bolt connection is removable, with hexagonal head bolts and cup head hexagonal bolts.

(2) Stud: no head, only the two ends of a class of fasteners with external threads. Connection, it must be screwed into one end with internally threaded holes in the parts, the other end through the parts with through holes, and then screwed on the nut, even if the two parts are tightly connected as a whole. This type of connection is called a stud connection and a removable connection. Mainly used for one of the parts being connected to a greater thickness, requiring a compact structure, or due to frequent disassembly, should not be used to bolt the occasions, double studs, full-threaded bars, and so on.

(3) Screws: also by the head and screw, two parts of the composition of a class of fasteners, according to the use, can be divided into three categories: steel screws, fastening screws, and special-purpose screws. Machine screws are mainly used for tightening threaded holes in the parts, and through-hole parts with a fastening connection between the parts, do not need to nut with (this form of connection is called screw connection and also belong to the removable connection; it can also be used with the nut with the two through-hole parts with a fastening connection between the parts.) Set screws are mainly used to fix the relative position between two parts. Special-purpose screws such as ring screws for lifting parts, cross pan head screws, hexagon socket set screws with flat ends, ring screws, etc.

(4) Nuts: with internally threaded holes, the shape is generally shown as a flat hexagonal column, but also a flat square or flat cylindrical, with bolts, studs, or steel screws used to fasten the connection between the two parts, so that it becomes a whole piece—hexagonal nuts, hexagonal flange nuts, hexagonal flange nylon lock nuts, etc.

(5) Self-tapping screws: similar to the screw, but the thread on the screw for the particular self-tapping screw thread. Used to fasten the connection of two thin metal components so that it becomes a whole, components need to be made beforehand on the hole because this screw has a high hardness and can be directly screwed into the components of the hole so that the components in the formation of the corresponding internal threads. This form of connection also belongs to the removable connection. Cross pan head tapping screws, flat-tailed cross round head tapping screws, etc.

(6) Wood screws: also similar to the screws, but the screw threads for the particular wood screws with threads, can be directly screwed into the wooden components (or parts), used to a metal (or non-metallic) with through-hole parts and a wooden component fastening connection together. This connection is also removable.

(7) Washers: the shape of a flat circular ring of a class of fasteners. Placed on the bolt, screw, or nut support surface and connecting parts between the surface play a role in increasing the contact surface area of the connected parts, reducing the pressure per unit area, and protecting the surface of the connected part from being damaged; another type of elastic washers, but also play a role in preventing the nut back to the role of loose.

(8) Retaining ring: for mounting in steel structure, equipment, shaft groove, or hole groove, plays a role in preventing the shaft or hole on the parts of the left and right movement.

(9) Pins: These are mainly used for part positioning, but some can also be used for part connection, fixed parts, transmission of power, or locking other fasteners.

(10) Solid rivets: the head and nail rod composed of two parts of a class of fasteners used to fasten the connection of two parts with holes (or components) to become a whole piece. This form of connection is called a riveted connection, referred to as riveting. It belongs to the non-removable connection. To connect the two parts separately, one must destroy the rivets on the parts.

(11) Flat washers, spring washers, bolt combination: a combination of parts is a combination of a class of fasteners, such as some machine screws (or bolts, self-supporting screws) and flat washers (or spring washers, lock washers) combination of supply; connecting the vice refers to some special bolts, nuts, and washers combination of the supply of a class of fasteners, such as steel structure with high-strength large hexagonal bolts connecting the vice.

(12) Welded screws: the light rod and nail head (or no nail head) constitute a different type of fastener, with the welding method to fix him connected to a part (or component) above to then connect with other parts.

Please get in touch with our team if you need high-quality, high-strength screws& fasteners with more detailed specifications and related information.

Email:adelajonly@gmail.com,www.juxinfasteners.com.

Thread identification and inspection solutions

1. Uses and characteristics of threads.

Threads are used extensively, from airplanes and automobiles to water pipes and gas used daily. Most threads play the role of fastening connection, followed by the transmission of force and movement, and some are special-purpose threads. Although there are many kinds of threads, their number is limited.

Threads can be durable because they have a simple structure, reliable performance, and ease of dismantling and manufacturing, among other characteristics. These characteristics make them an indispensable structural element in various electromechanical products nowadays.

According to the use of thread, all kinds of threaded parts should have the following two most basic functions: one is good screwing, and two is enough strength.

2. Classification of threads

a. Its structural characteristics and use can be divided into four categories:

Ordinary thread (fastening thread): This thread shape is triangular and is used for connecting or fastening parts. Common threads are divided according to the pitch into coarse and fine threads, and the connection strength of fine threads is higher.

Transmission threads are trapezoidal, rectangular, saw-shaped, and triangular.

Sealing threads: These are used for sealing connections, mainly pipe threads, tapered threads, and tapered pipe threads.

Special purpose threads are referred to as special threads.

b. Threads by international standards can be divided into metric threads (metric threads), British threads, American threads, etc.; we are accustomed to British threads and American threads, collectively referred to as British threads, which have a tooth angle of 60 °, 55 °, etc., diameter and pitch and other related thread parameters using the British size (inch). In our country, the tooth angle is standardized as 60°, and the diameter and pitch in millimeters (mm) are used, while such threads are named common threads.

What are the common thread types for fasteners?

S.W.: British Standard Whitworth thread (coarse thread) BSF---- British Standard Whitworth thread (fine thread)

R: conical pipe thread (old code Z.G., K.G.) R.C. ---- conical pipe thread (old code Z.G., K.G.)

G: straight pipe thread (external threads A, B two-sided level, tap G, G-D)

U.S. system threads (thread type 60 degrees):

UNC: Unified Coarse Thread (instead of N.C.) UNF --- Unified Fine Thread (instead of N.F.)

UNEF: Unified extra fine threads U.N. ---Unified constant pitch threads

UNS: Unified Special Threads NPT --- American Standard Tapered Pipe Threads

NPSC: American Standard Straight Pipe Threads for Pipe Fittings NGT---Tapered Threads for Gas Cylinders

NPTF: Dry Seal Tapered Pipe Threads NPSF--Straight Pipe Threads for Dry Seal Fuel Fittings

NPSM: American Standard Straight Pipe Threads for Mechanical Connections NPTR---American Standard Tapered Pipe Threads for Guide Rods:

NPSL: American Standard straight pipe threads for pipe locknuts NPSH---American Standard straight pipe threads for hose connections

Metric Series Threads: It refers to a series of metric threads developed by the International Organization for Standardization (ISO), including M1.6, M2, M2.5, M3, M4, M5, M6, M8, M10, M12, M14, M16, M18, M20, M22, M24 and other specifications. M series threads are widely used in mechanical parts and are a common fastener thread.

UNC thread: It refers to a series of uniform coarse threads developed by the American National Standards Institute (ANSI), which are mainly used for corrugated sheets, thin plates, various pipes and fittings, all kinds of screws, and the vast majority of the mechanical structure of the threaded connection. Common specifications are 1/4, 5/16, 3/8, 7/16, 1/2, 5/8, 3/4, 7/8, 1, 1 1/8, 1 1/4 and so on.

UNF Thread refers to a series of uniform fine threads developed by the American National Standards Institute (ANSI), which apply to various mechanical structures and automotive parts. Common specifications are 1/4-28UNF, 5/16-24UNF, 3/8-24UNF, 7/16-20UNF, 1/2-20UNF, 5/8-18UNF, 3/4-16UNF and so on.

BSW thread: It refers to a series of coarse threads developed by the British Standards Institution (BSI) for non-motorized vehicles, machine tools, ships, construction, etc. The commonly used specifications are 1/8, 1/4, 5/16, 3/8, 7/16, 1/2, 5/8, 3/4, 7/8, 1, 1 1/8, 1 1/4, 1 1/2, 2 and so on.

BSF thread is a series of fine threads formulated by the British Standards Institute (BSI) for high-precision machinery and aviation. Common specifications are 1/4-26BSF, 5/16-22BSF, 3/8-20BSF, 7/16-18BSF, 1/2-16BSF, 5/8-14BSF, 3/4-12BSF, etc.

TR thread refers to a series of metric fine threads formulated by the Japanese Industrial Standard (JIS), suitable for high-precision mechanical structures such as precision instruments and fittings. Commonly used specifications are TR4, TR5, TR6, TR8, TR10, TR12, TR14, TR16, TR20, etc.

There are many kinds of fastener threads, and we commonly use metric threads M, UNC, UNF, BSW, BSF, T.R., and other thread types in our daily lives. Reasonable thread type selection is essential to ensure the stability and performance of the mechanical structure.

Basic Thread Terminology

Thread: A continuous protrusion with a defined tooth pattern formed along a helical line on a cylindrical or conical surface.

External threads: threads formed on the outer surface of a cylinder or cone.

Internal threads: internal threads formed on the inner surface of a cylinder or cone.

Large diameter: the diameter of the imaginary cylinder or cone tangent to the top of the external thread or the bottom of the internal thread.

Small diameter: an imaginary cylinder or cone tangent diameter to the bottom of the external thread or the top of the internal thread.

Median: The diameter of an imaginary cylinder or cone whose busbar passes through a groove in the tooth pattern and a projection of equal width. An imaginary cylinder or cone is called a center-diameter cylinder or center-diameter cone.

Right-hand threads: threads screwed in when rotated clockwise.

Left-hand thread: Threads that are screwed in when rotated counterclockwise.

Tooth angle: the angle between two neighboring teeth on a threaded tooth.

Pitch: The axial distance between two adjacent teeth at two points on the center diameter line.

Thread marking standard

Thread marking refers to the method of marking with specific symbols in the place where screws are required. Threads can be divided into two categories, coupling threads and transmission threads, according to their use, and standard markings include common threads and pipe threads.

In the drawing, threads need to be marked with the specified thread code, except for pipe threads; the marking format of the thread code is as follows: Characteristic code Nominal diameter × Pitch (for single thread) Rotation Conductivity (P pitch) (for multiple threads) The marking format of pipe threads is as follows: Characteristic code + Size code + Rotation Among them, the right-hand threads are omitted without notation, and the left-hand threads are indicated by "L.H." is used for left-hand thread.

Metric thread marking:

In general, a complete metric thread marking should include the following three aspects:

A.Thread type code indicating the thread characteristics;

b . Thread size: Generally, it should be composed of diameter and pitch, and for multi-threads, it should also include lead and number of threads;

c. Thread accuracy: the accuracy of most threads is determined by the tolerance zones (including the location and size of the tolerance zones) and the screwing length of the respective diameters.

Inch thread markings:

U.N.： A flat root contour is specified, but it is necessary to provide for some threading tool crest wear. Hence, a rounded root contour cleared beyond the 0.25p flat width of the Basic Profile is optional.)

UNR： To reduce the threading tool crest wear rate and improve the fatigue strength of a flat root thread, the Design Profile of the UNR thread has a non-reversing continuous curved root tangent to the thread flanks at a depth of 0.625 H.)

UNC： Coarse-Thread Series)；

UNF： Fine-Thread Series)；

UNEF：Extra-Fine-Thread Series)；

UNS： Selected Combinations和 Other Threads of Special Diameters, Pitches, and Lengths of Engagement)； Constant Pitch Series)，8UN、12UN、16UN and so on.

Inch uniform threads are divided into three series: coarse thread series UNC, fine thread series UNF, extra fine thread series UNFF, plus a fixed pitch series U.N.

Marking Method: Thread Diameter - Number of Threads per Inch Series Designator - Accuracy Grade

Example: Coarse Thread Series 3/8-16 UNC-2A

Fine Thread Series 3/8-24 UNF-2A

Extra Fine Series 3/8-32 UNFF-2A

Fixed-Pitch Series 3/8-20 UN-2A

The first digit, 3/8, indicates the outer diameter of the thread in inches, which is converted to metric unit mm by 25.4, i.e., 3/8×25.4=9.525mm; the second and third digits, 16, 24, 32, 20 are the number of threads per inch (the number of threads on the length of 25.4mm); the third digit after the text designation of UNC, UNF, UNF, UNFF, U.N. is the series designation, and the last two digits 2A are the accuracy level. The previous two 2A are precision grades.