国产精品毛片一区二区三区,国产女人被狂躁到高潮小说,国产91精品一区二区麻豆网站,日韩精品人妻丰满-无码久久

Note: 1st, the belt * mark’s variety for the commodity fastener variety, should first select uses.
2nd,①Tapping screw’s thread tolerance, according to the GB5280 stipulation.
3rd,②Tapping screw’s mechanical property, according to the GB3098.5 stipulation.
4th,③From attacks gib screw’s thread tolerance, according to the GB6559 stipulation.

Tapping screw’s use synopsis

The tapping screw uses in the thin metal plate (steel plate, saw board and so on) between connection. When connection, to is generated first by the bridge piece the thread bottom hole, then installs the tapping screw by in bridge piece’s thread bottom hole. Because tapping screw’s thread surface has the high degree of hardness (≥HRC45), may in attack by in bridge piece’s thread bottom hole the box thread, thus forms the connection.
　　 From attacks the set screw also to use between the thin metal plate the connection. Its thread to have the arc triangle section plain thread, the thread surface also has the high degree of hardness, therefore when connection, the bolt may also in attack by in bridge piece’s thread bottom hole the box thread, thus forms the connection. This kind of bolt’s characteristic has installs the moment of force and the high locking performance lowly, has the better operating performance compared to the ordinary tapping screw, and may replace the machine screw use.
　　 The wall plate tapping screw uses in the gypsum wallboard and so on and between the metal keel’s connection. Its thread is the double thread, the thread surface also has the very high degree of hardness (≥HRC53), can, in does not generate the prefabricated hole under the condition, installs in fast the keel, thus forms the connection.
　　 From drills the tapping screw and the ordinary tapping screw difference is the ordinary tapping screw when the connection, must (drill thread bottom hole) after the drill hole and attacks the silk (including fastening connection) two working procedures; But from drills the tapping screw when the connection, will drill a hole and attacks the silk two working procedures to merge a time to complete. It uses in front of bolt’s drill bit to carry on the drill hole first, then uses the bolt to carry on attacks the silk (including fastening connection), saves the construction time, raises the construction efficiency.
　　 The women’s hairdo with hair in a spiral on top or behind the head and the hexagonal head tapping screw is suitable the situation which reveals in the drill bit permission, the hexagonal head tapping screw may compared to the women’s hairdo with hair in a spiral on top or behind the head tapping screw along with the big moment of force. Sinks and in six corner decorations shape tapping screw is suitable the situation which does not allow in the nail head to reveal, in six corner decorations shape tapping screw may compared to the quiet tapping screw withstanding big moment of force; Half quiet tapping screw is suitable the situation which reveals slightly in the nail head permission. When tapping screw’s assembling and dismantling, the slot tapping screw needs in-line bolt to turn on lathe has, the cross trough tapping screw needs the cruciform bolt to turn on lathe has, in six corner decorations shape tapping screw needs six corner decorations shape spanner, the hexagonal head tapping screw needs the dull spanner, the box wrench, the volume box or the adjustable spanner.