Qingdao Haorui Steel Products Co., Ltd.
Mob: 15966945003
Contact: Yanan Wang
Tel: 0532-87881070
Fax: 0532-87980111
Email: wang@qdhaorui.com
Add: No. 375, Zhengyang East Road, Xifu Town, Chengyang District, Qingdao
What are the main geometric parameters of self-tapping and self-drilling bolt threads?
How to specify the outer diameter of the thread, the diameter of the root, the pitch, the number of threads, the angle of the tooth, and the angle of the tail tip of the self-tapping bolt? We made a brief introduction.
(1) Major diameter/tooth outer diameter (d1), which is the diameter of the imaginary cylinder where the thread crest overlaps. The major diameter of the thread basically represents the nominal diameter of the thread size.
(2) Minor diameter/bottom diameter (d2): the diameter of the imaginary cylinder where the thread bottom overlaps.
(3) Tooth pitch (p): It is the axial distance between two adjacent teeth corresponding to two points on the middle meridian. In the imperial system, the number of teeth per inch (25.4mm) is used to indicate the pitch.
The following table lists the common specifications of the pitch (metric system) and the number of teeth (imperial system)
1. Metric self-tapping:
specification | ST 1.5 | ST 1.9 | ST 2.2 | ST 2.6 | ST 2.9 | ST 3.3 | ST 3.5 | ST 3.9 | ST 4.2 | ST 4.8 | ST 5.5 | ST 6.3 | ST 8.0 | ST 9.5 |
Tooth pitch | 0.5 | 0.6 | 0.8 | 0.9 | 1.1 | 1.3 | 1.3 | 1.3 | 1.4 | 1.6 | 1.8 | 1.8 | 2.1 | 2.1 |
2. Inch self-tapping:
specification | 4# | 5# | 6# | 7# | 8# | 10# | 12# | 14# | |
tooth number | AB teeth | 24 | 20 | 20 | 19 | 18 | 16 | 14 | 14 |
A tooth | 24 | 20 | 18 | 16 | 15 | 12 | 11 | 10 | |
3. Japanese standard wallboard nails:
specification | 6# | 7# | 8# | 10# | |
Coarse teeth | Number of teeth | 9 | 9 | 9 | 8 |
Tooth pitch | 2.82 | 2.82 | 2.82 | 3.18 | |
Fine teeth | Number of teeth | 18 | 16 | 15 | 12 |
Tooth pitch | 1.41 | 1.59 | 1.69 | 2.11 | |
4. Mechanical screws (mechanical teeth):
specification | Metric system (tooth pitch) | British system (number of teeth) | ||||||||||||
M2.5 | M3 | M3.5 | M4 | M5 | M6 | M8 | 4# | 5# | 6# | 8# | 10# | 12# | 1/4 | |
Coarse teeth | 0.45 | 0.5 | 0.6 | 0.7 | 0.8 | 1.0 | 1.2 | 40 | 40 | 32 | 32 | 24 | 24 | 20 |
Fine teeth | 0.35 | 0.35 | 0.35 | 0.5 | 0.5 | 0.75 | 1.0 | 48 | 44 | 40 | 36 | 32 | 28 | 28 |
5. Self-drilling screws: There are two types of self-drilling screws: CSD (mechanical thread) and BSD (self-tapping AB thread). The pitch or number of teeth can refer to machine screws (CSD teeth) and self-tapping screws (BSD teeth) respectively.
(4) Asan angle and tail apex angle: Asan angle is the angle between the flank and the flank, and the tail apex angle is the tip angle of the thread.
1. Self-tapping teeth: Asan angle is 60O, tail tip angle is 45O±5O.
2. Wallboard nails: Asan angle is 60O, (also can be produced according to customer requirements, such as 45O±5O) tail tip angle is 25O±3O.
3. Splint screws: (Chip board screws) the angle of the tooth mountain is 40O±3O, and the angle of the tail tip is 25O±3O or 34O±3O (customer special requirements).
4. Tail-drilling screw: Asan angle is 60O±5O. Different types of tail-clamping pins are selected for products of different specifications. The main geometric parameters of the tail-clamping are the diameter and extension of the tail.
