Representation And Grades Of Outer Hexagon Bolts

Outer hexagon bolt is a very common fastener, and it is widely used in many fields. Maybe someone would like to know more about the outer hexagon bolt. As a professional fastener manufacturer, Xinchi Fastener Company is very pleased to introduce the representation of hexagonal bolts and the grade of hexagonal bolts.

Method for expressing dimensions of outer hexagon bolts

Bolt specification M14 indicates a metric bolt with a thread length of 14mm. M stands for “metric” thread. The complete thread marking is composed of: thread characteristic code + dimension code + tolerance code + and other information + standard code (for example, add national standard code for domestic screws)

The characteristic code of thread is represented by the letter “M”.

Size code: The size code of a single thread is “nominal diameter × screw moment”.

The tolerance belt code is represented by a number plus a letter (uppercase letter for internal thread, lowercase letter for external thread), such as 7H, 6g, etc. It should be noted that 7H, 6g, etc. represent thread tolerances, while H7 and g6 represent cylinder tolerances.

The binding length is defined as short (denoted by S), medium (denoted by N), and long (denoted by L). In general, the screw length is not marked, and the thread tolerance zone is determined by the medium screw length (N). If necessary, the screw length code S or L can be added, such as “M20-5g6g-L”. In the case of special needs, the value of the screwing length can be indicated, such as “M20-5g6g-30”.

Left-hand threads should be marked “LH” after the length of the screwing. Use “-” to separate the length code and the turn code, and omit the right-hand thread.

Marking example: M 16-5G6g indicates coarse ordinary thread, nominal diameter is 16, right-handed, thread tolerance zone is 5g, large diameter 6g, screw length is considered as medium length.

Class of outer hexagon bolts

There is a standard for external hexagon bolts, which is classified into 4.8 and 8.8. Most of these two levels on the market are 4.8 external hexagon bolts because it is more affordable than 8.8 external hexagon bolts, which are of course more widely used. But for some demanding products, due to its hardness and other aspects of the high requirements, it is necessary to use 8.8-level hex bolts. From the hardness and screw torque and other aspects, 8.8 class external hexagonal bolts are harder, more secure, tighter, and more stable for the use of products.

Anji Xinchi Fastening Piece Co., Ltd is a trustworthy fastener company, especially in furniture nuts. And we are the designated fastener supplier to“STAPLE”. As a trusted fastener supplier,  Xinchi Fastener Company can offer a wide range of high-quality fasteners, including tee nuts, screws, bolts, rivets, washers, etc. If you want to know more about fasteners or want to wholesale fasteners, please feel free to contact us. And then our experienced and expert service team will reply to you as soon as possible.