Now the production of ordinary nails can be very simple and convenient, can in a very short period of time, to achieve high-volume shipments, because by the machine to complete, more quickly than our human eyes and hands fit. But we ought to grasp and control late check material in two ways. The former must spare no effort, because he can not be able to withstand sufficient weight, or let loose items together, we must look at how its material. Although unlike some nails so hard, such as concrete nails, but the minimum hardness must ensure that not a hammer down on the fold in half. In the latter regard we need to carefully examine it and generally look gloss, stiffness, it is not straight and so on.