Although from the outside, Tian Mobiyu and Hetian Moyu are basically unable to distinguish, they are all black. Let many consumers can't tell which one is the ink, which is the ink jade, and it is difficult to identify Hetian jade jade and ink? However, the use of a strong light flashlight can distinguish between the two, the white light is Hetian Moyu, and the green light is the ink jasper. In addition to seeing the color identification of light, we can also identify the two by the intensity of light transmission. The light intensity of Hetian Mobiyu will be much stronger than that of the ink jade. The light is green, and the light of the jade is white. It can be well identified by using a flashlight. The identification of black kava and Hetian Moyu makes it easier to use a flashlight. After being irradiated with a flashlight, the kava stone belongs to the stone after all, and will not transmit light; and Hetian Moyu will transmit light. Everyone must remember the fundamental difference when identifying Hetian jade and stone, that is, jade will transmit light, while ordinary stone will not transmit light. A little bit of experience, friends can also be identified by the appearance of the luster and jade is oily or dry. Hetian jade jade and ink, kava stone identification can use flashlight, in fact, many other jade identification can also use the flashlight to view the internal structure to identify, it can be said that the flashlight is an artifact to identify Hetian jade. Self-tapping Screws have a wide range of tip and thread patterns, and are available with almost any possible screw head design. Common features are the screw thread covering the whole length of the screw from tip to head and a pronounced thread hard enough for the intended substrate, often case-hardened. stainless steel self tapping screws, pan head self tapping screws, flat head self tapping screws FinExpress Precision Manufacturing(Dongguan) Co., Ltd , https://www.finexpresshardware.com
For hard substrates such as metal or hard plastics, the self-tapping ability is often created by cutting a gap in the continuity of the thread on the screw, generating a flute and cutting edge similar to those on a tap. Thus, whereas a regular machine screw cannot tap its own hole in a metal substrate, a self-tapping one can (within reasonable limits of substrate hardness and depth).
For softer substrates such as wood or soft plastics, the self-tapping ability can come simply from a tip that tapers to a gimlet point (in which no flute is needed). Like the tip of a nail or gimlet, such a point forms the hole by displacement of the surrounding material rather than any chip-forming drilling/cutting/evacuating action.
Not all self-tapping screws have a sharp tip. The type B tip is blunt and intended for use with a pilot hole, often in sheet materials. The lack of a sharp tip is helpful for packaging and handling and in some applications may be helpful for reducing the clearance necessary on the reverse of a fastened panel or for making more thread available on a given length screw.