How to distinguish screw specifications and models


Screw nuts are not unfamiliar to product designers. In […]

Screw nuts are not unfamiliar to product designers. In fact, from the beginning of the sensible screw has a preliminary understanding of everyday life can be seen everywhere, from housing decoration, small to computer mobile phones. But when we develop new products, there is always a kind of inexplicable embarrassment that we can't find, such as the size and thickness of the nut, the length of the screw, and the screw with special requirements.

Next, I will summarize the specifications and models of the nuts and screws that we often use in the structure of electronic products, so that we can find them better in the follow-up work.

01, screw production standard

GB - China National Standard (GB) ANSI - American National Standard (US Standard)

DIN-German National Standard (German Standard) ASME-American Association of Mechanical Engineers Standard

JIS-Japanese National Standard (Japanese Standard) BSW-British National Standard

ISO-International Standard

GB - national standard is one of many standards in our country. In addition, there are industry standards, professional standards and some standards. National standards are divided into: GB (compulsory standard), GB/T (recommended standard) and GBn (national internal standard). What we usually see, like GB30, GB5783 and so on, are mandatory standards.

In addition to some basic sizes such as head-to-side, head thickness and so on, the main difference among the above standards is the threaded part. The threads of GB, DIN, JIS and so on are all in MM (millimeter) units, collectively known as metric threads.

Common screw classifications are as follows:

PA--round head pin screw

PB-round head flat foot screw

PT--round head pin screw

BA-Big Head Toe Screw

BT--Flat-footed Medium-foot Screw

KA-Flat-Headed Toe Screw

KB-Flat Head Flat Foot Screw

KT-Flat Head Interpodal Screw

PWA/WA--With Meson Pin Screw

PWB/WB--Flat Foot Screw with Meson

PWT/WT--Mesopin Screw with Meson

PM--Tooth Screw for Round Head Machine

KM-Flat Head Flat Foot Machine Tooth Screw

Hexagonal machine tooth screw

Code description: A-pointed feet; B-big head, flat feet; M-machine teeth; K-flat head; P-round head; T-intermediate feet; W-banded meson.