How to use stud bolt

This kind of double head with self tapping screw is generally used in furniture.

1. Fix two nuts on the normal thread end and tighten them alternately. Then screw the upper nut with a wrench and screw the self tapping screw into the matrix until it can not be screwed（ This method is also used when this screw is screwed out, but the lower nut is screwed out with a wrench.)

2. Then use two spanners to screw the nut in the opposite direction at the same time, loosen the nut, so that the two nuts can be backed out.

3. Pass the fastener (generally with through hole) through the normal thread end, add gasket, and tighten the nut normally.

说一下为什么要用这种螺丝，这种螺丝一般用在需要经常拆卸的场合，因为自攻端一旦拆出，就不好用了，所以采用这种双头螺丝避免拆出自攻螺丝端，需要拆卸时只要把螺母拧下，就能拆掉后装上去的件儿，防止了自攻端受到破坏。