Specification
What is a one-way screw?
It is also known as tamperproof screws, security screws and one direction tightening the screws.
It is a special screw and can lock by only one direction, because the recess of screw is tilt. One-way screws can only allow a screwdriver in one direction to move the screw.
Which one is strict? 2A or 3A toward the thread gage?
We often can see the thread gauge indicated in 2A and 3A or 2B and 3B, and we are easily to mislead 3A stricter than 2A or 3B stricter than 2B.
In fact, there is no difference on grade, and only different on the thread size range requirements. For example, the dimension tolerance of 6#-32 UNC 2A O.D. is 0.1372’’~0.1312’’, and 6#-32UNC 3A O.D. is 0.1380’’~0.1320’’. Both tolerances range are 0.006 inch, so 3A is not stricter than 2A.
螺絲常見的牙紋有？
Self-tapping thread, machine thread, triangular thread and so on.
