All the screws we use in daily life have national standards, and the description of a screw is M to indicate the diameter. For example, M12 screws indicate that the thread diameter is 12mm. All the screws in the national standard are produced by the thread rolling machine, and the thread rolling template is also formulated according to the national standard. The wire diameter of the screw before turning also has a corresponding standard, otherwise the thread rolled out cannot pass the go no go gauge test. The go no go gauge test of the thread is a national mandatory standard, which is the main test method to determine whether a screw is qualified.
Can hot-dip galvanized screws be inspected by go no go gauge? We often encounter users to ask us about this problem. When purchasing, we are worried about the problems of the goods. When signing the contract, we will ask for the inspection standard to be written down. Many users say that after receiving the goods, the thread go no go gauge inspection should be carried out. Here we need to explain that the hot-dip galvanized screw products can not go through the go no go gauge. This inspection method is only for standard screws. Screws without treatment can be inspected in this way, The surface treated screws cannot be tested by this method.
Don't mention the hot-dip galvanized screw. Even the galvanized screw can't pass the go no go gauge sometimes. No matter how thick the galvanizing is, the general gauge adds a layer of protective film on the standard, and the hot-dip galvanized protective film is the last, so it is impossible to detect the thread through the go no go gauge. How do we detect whether it is standard? In fact, it is only necessary to measure the thickness of the zinc layer. Let's look at the standard thread parameters in the national standard:
The small specifications above do not need to be considered, and the screws of this specification are not used for hot plating. Besides, zinc plating is the most important.
The above thread is the thread standard that can be used for hot galvanizing. The parameters in it are the national standards adopted in normal production. These are the parameters that can pass through the go no go gauge. After the production is completed, as long as the hot-dip galvanizing treatment is carried out, these parameters will all change, and the parameters will all change. How can we go no go gauge test again?
Even some pin shaft parts are produced according to the national standard, and all tolerance dimensions are within the detection range. However, as long as hot-dip galvanizing is carried out, its detection method cannot be carried out according to the national standard, which is not a quality problem, but a way to adapt in practical application. Only stainless steel screws can be directly inspected by go no go gauge after production.
