1. Depth of punching hole: the depth of concrete construction is better than the length of the expansion pipe is about 5 mm deeper. As long as it is greater than or equal to the length of the expansion tube, the length of the steel drop in anchor left in the ground is equal to or less than the length of the expansion tube.
2. The requirements of the steel drop in anchor on the ground are of course the harder the better, which also depends on the stress of the objects you need to fix. The mechanical strength installed in the concrete (C13-15) is five times that of the brick.
3. After an M6/8/10/12 internal expansion bolt correctly installed in the concrete, its optimal maximum static force is 120/170/320/510 kg, respectively. The installation method of the internal expansion bolt is not very difficult. The specific operations are as follows; first, select an alloy drill bit with the same diameter as the expansion screw expansion ring (tube), install it on the electric drill, and then drill the wall. The depth of the hole is preferably the same as The bolts have the same length, and then lower the expansion screw set into the hole together, remember; do not unscrew the screw, to prevent the bolt from falling into the hole when the hole is deeper, and it is not easy to take it out. Then tighten the nut 2-3 buckles and feel that the steel drop in anchor are tighter and not loosen, then unscrew the nut.