Screws tell you: how to install the combination of screws
Combination screw is a screw only with a spring pad or only with a flat pad, or also only with a flower teeth of the two combinations of parts. So today tell you how the combination of screws should be installed?
1、Drilling
Use the standard drill bits listed in the table, drilling depth greater than or equal to the installation depth of the combination of screws; note that the hole is not drilled into a cone, chips do not fall into. After drilling the countersink should not exceed 0.4 pitch depth, because the countersink is too large for the combination of screws screwed into.
2、Tapping
Use the combination of screw tapping taps marked with the specified thread specifications, the length of the tapping must exceed the length of the combination of screws, for through holes, to all tapping, tapping accuracy determines the tolerance zone of the final standard internal screw hole, the user should properly select the tapping method and lubrication, blind hole tapping with appropriate force, to prevent breaking the tap. After tapping, the threaded hole should be cleaned, usually with a compressed air gun blowing, blind holes should also use a long gun with radial holes from the bottom up to clean, you can also use the cleaning method to clean the threaded hole. When the accuracy of the threaded hole is high, a special combination of screw bottom hole plug gauge should be used to check.
3, installation
In general, under the hole, and make it from the surface to leave 0.25-0.75 turns of empty thread. A small number of installation of combination screws and M14 × 2 above coarse tooth combination screws can be installed using a "T" slotted or threaded head simple tool, and pay attention not to apply a large axial force on the combination screw mounting shank to prevent "messy buckle". After the installation of the combination screw, in order to check the accuracy level of the standard internal thread hole formed, the corresponding level of plug gauge inspection is available.
4、De-shanking
For the combination of screws with fracture groove, screwing into the screw hole should be installed after the removal of the shank, you need to use the shank removal tool. Through the hole, to break the combination screw mounting shank, generally with a punch to the mounting shank, with a hammer of about 200g can be removed, for M18 × 2.5 above the coarse teeth combination screws and M14 × 1.25 above the fine teeth combination screws, bend the mounting shank up and down with sharp pliers can be broken, and then remove the broken mounting shank from the screw hole.