To fix any object on a metal surface, fasten metal structures or attach a metal profile to wood or other material, use metal screws. These hardware are convenient, but it is not always possible to drive them into the surface without first perforating it.
Instructions
Step 1
Self-tapping screw - one of the most popular hardware, is often used for repairs and in various designs, it is beneficial in that it reduces the cost of time and labor.
Step 2
Self-tapping screws are made of high-carbon steel with an oxidized coating. They are produced in various lengths, diameters and can have different thread pitches. Depending on the application, metal screws are of various types. For easy screwing, holes are usually pre-drilled in the parts to be fastened. But these holes must be drilled taking into account the thickness of the metal and the type of hardware. For example, metal structures are connected with self-tapping screws with a press washer and with a drill at the end, sheets up to 2 mm can be fastened without drilling holes.
Step 3
Self-tapping screws with press washers and sharp tips are used to attach metal products to other materials. If the thickness of the steel sheet is up to 0.9 mm, without pre-drilling.
Using black self-tapping screws for metal, tin is attached to wooden bases without drilling, and when the sheet thickness is more than 2 mm, it is already necessary to drill a hole.
Step 4
The hole is drilled in two blanks at once, which are pre-installed in the desired position. Drills for the device of holes for self-tapping screws must be used universal for metal.
Step 5
The upper part is drilled with a larger diameter than the self-tapping screw in order to have a pressing effect. The lower surface is drilled with a diameter equal to the screw diameter minus two thread heights (the distance from the top of the thread to the base of the profile, measured perpendicular to the axis of the screw).
The diameter of the self-tapping screw is determined by the markings in the store or measured with a caliper independently.
Step 6
As the thickness of the metal increases, so does the diameter of the drill. For example, for a self-tapping screw with a press washer and a sharp tip and with a tip in the form of a drill, an increase in the sheet thickness by 0.5 mm leads to an increase in the drill diameter by 0.1 mm.
Step 7
For black self-tapping screws with a sharp tip, when the metal thickness is increased by 0.5 mm, the drill diameter should be increased by 0.2 mm. The depth of the hole should be slightly more than the length of the self-tapping screw.
Step 8
After the hole is ready, it must be cleaned and oiled. The self-tapping screw can be screwed in with a screwdriver with an appropriate head or a screwdriver.
