Bolt specification method, expansion bolt specification table

I believe that everyone is no stranger to bolts. It is possible to use bolts in various lamps, furniture, etc. in the home. There are many sizes of bolts, big and small. What is the bolt specification? What is the expansion bolt specification table? Let's take a look at it next.

What is a bolt ?

Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread) that is to be fitted with a nut for fastening two parts with through holes. This type of connection is called a bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

Bolt specification representation :

Bolt size M14 indicates a metric bolt with a thread diameter of 14 mm. M means "metric, metric" thread. The complete thread mark is composed of: thread feature code + size code + tolerance band code + and other information + standard code (such as: domestic screw plus national code)

1. The characteristic code of the thread is the letter "M"

2, size code

The size code of the single thread is "nominal diameter x screw moment". For the coarse thread, the item of the moment can be omitted. The size code of the multi-thread thread is "nominal diameter × Ph lead P pitch".

3, tolerance band code by the number plus letters (internal thread with uppercase letters, external thread with lowercase letters), such as 7H, 6g, etc., should be specified, 7H, 6g, etc. for thread tolerance, and H7, g6 for cylinder tolerance Code.

4. The screw length is defined as three types: short (indicated by S), medium (indicated by N), and long (indicated by L). In general, the threaded length is not marked and the thread tolerance band is determined by the medium twist length (N). If necessary, the screw length code S or L can be added, such as "M20-5g6g-L". For special needs, indicate the value of the length of the screw, such as "M20-5g6g-30".

5. The left-hand thread should be marked “LH” after the screw length. The screw length code and the direction code are separated by "-", and the right-hand thread is omitted.

6, tag example:

M 16-5g6g means the common thread of coarse teeth, nominal diameter 16, right-handed, thread tolerance with medium diameter 5g, large diameter 6g, and the length of the screw is considered to be medium length.

M16×1 LH-6G means ordinary thread of fine teeth, nominal diameter 16, pitch 1, left-handed, thread tolerance with medium diameter and large diameter of 6G, and the screw length is considered by medium length.

What is an expansion bolt?

Expansion bolts are special threaded connections used to secure pipe supports/cranes/brackets or equipment to walls, floors, and columns. The principle of the expansion bolt is to hit the expansion bolt into the hole on the ground or the wall surface, and then tighten the nut on the expansion bolt with a wrench, the bolt goes out, and the outer metal sleeve does not move, so the big head under the bolt is put The metal sleeve is opened so that it fills the entire hole, at which point the expansion bolt will not be pulled out.

Expansion bolt specification table:

Editor reminder:

The above is the bolt specification and the expansion bolt specification table that I introduced to you. A seemingly ordinary expansion bolt, there is a large potential risk factor, because the expansion screw is not selected, and it is harmful to public safety, the expansion bolt is not selected well, and even endangers the life of the family. The expansion screw does not meet the standard tensile force and the shear force is unqualified. It will cause serious public hazards, so it is especially important to choose a good quality expansion bolt. When buying expansion bolts, be sure to compare them. Ask the store if there is any better quality. Take a look at Bibi. Only by purchasing the genuine national standard expansion bolt can the family's life be guaranteed, the public hazard reduced, and public safety improved.