The installation process of the combination screw
1. Drilling
Use the standard drill bit listed in the table to drill the hole to a depth greater than or equal to the mounting depth of the combination screw; be careful not to drill the hole into a tapered shape and to prevent chips from falling into it. After drilling, the countersinking hole should not exceed the depth of 0.4 pitch, because the oversized countersinking hole is not conducive to the screw-in of the combination screw.
2. Tapping
Use the special tap for the combination screw marked with the specified thread standard. The length of the tapping must exceed the length of the combination screw. For the through hole, all the tapping is required; the accuracy of the tapping determines the final standard of the internal tap hole. To properly select the tapping method and lubrication, the blind hole tapping should use appropriate force to prevent the tap from breaking. After tapping, the threaded holes should be cleaned, generally with a compressed air spray gun, and a long spray gun with radial holes should be used to clean the blind holes from bottom to top, and the threaded holes can also be cleaned by cleaning. When the threaded hole accuracy is high, use a special combination screw bottom hole plug gauge for inspection.
3. Installation
In general, the hole should be left with 0.25-0.75 circles of empty thread from the outer surface. When installing a small amount of combination screws and when installing a combination screw with a coarse thread of M14×2 or more, it can be installed with a "T" slot or a threaded head. clutter”. After the combination screw is installed, in order to check the accuracy grade of the standard internal thread hole formed, the corresponding grade plug gauge can be used to check.
4. Remove the handle
For a combination screw with a broken groove, the mounting handle should be removed after screwing into the screw hole, and the handle should be removed. In the case of through-holes, the mounting handle of the combination screw should be broken. Generally, use a punch to align the mounting handle, and use a hammer of about 200g to remove it. For the combination screws with coarse teeth above M18×2.5 and those above M14×1.25 The fine-tooth combination screw can be broken by bending the mounting handle up and down with needle-nose pliers, and then remove the broken mounting handle from the screw hole.
