How To Make A Hole In A Metal Without A Drill
We will tell and teach
Why do some people drill metal quickly and without too much difficulty, while others resemble an epic accompanied by broken and dull drills?
Metal parts are typically drilled using twist drills having two cutting edges in the working part and two helical grooves for chip evacuation.
The most common are drills made of P6M5 steel, drills with cobalt in the marking are marked with the letter K (P6M5K5), such a tool dulls more slowly, but also costs more.
Drills with titanium spraying have higher strength indicators. They differ from the rest of the tool in a yellow coating.
In addition to spiral drills, there are also step-like ones that have a Christmas tree view in longitudinal section. Made of high-speed steel, they have a pitch of 2 mm, which makes it possible to make holes in the sheet metal with diameters from 4 to 36 mm.
Lubrication and cooling
During metal drilling, the drill can become very hot under the influence of friction. Due to overheating, the hardness of the drill decreases and it loses its cutting properties.
This can be avoided both by cooling the drill and by reducing friction. For the simultaneous lubrication and cooling of the drill, there are special cutting fluids and paste formulations.
Before starting work, a liquid lubricant is applied to the drill with a brush or inserted into the drill hole with an oil can, and the paste is applied to the drill immediately before drilling.
At home, in the absence of special tools for lubrication and cooling, you can use machine oil, ordinary gray cast iron is drilled “dry”.
Before starting drilling, be sure to apply a small indentation in the center of the future hole with a core and a hammer.
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This will avoid leaving towards the drill in the initial stage of its cutting into the metal.
Place a trimmed board of the appropriate size under the metal workpiece. The part will slide less, and the edges of the outlet opening will be much cleaner.
Hold the drill so that the drill is located strictly perpendicular to the plane of the workpiece. Otherwise, the drill will deviate from the intended axis, and a thin one may break at all.
Significantly facilitates the use of a special drill stand, spacers or rails.
At the initial stage of drilling, pressing the drill should be barely noticeable. As the drill cuts into the metal, the pressure can be slightly increased.
An indicator of the correct choice of effort for pressing is the chip produced by the drill.
Small crumbs indicate that the pressure needs to be increased, thin chips indicate normal flow, and thick spiral chips indicate a need to reduce the force on the drill.
Beginners make the most mistakes when choosing the drilling speed of the metal, setting the rotation speed of the drill too high. As a result, the drill overheats, quickly dulls and becomes unusable.
When drilling metal with a drill with a diameter of 3-4 mm, its rotation speed should not exceed 1000 revolutions per minute. With an increase in the diameter of the drill, the speed of the drill should be proportionally reduced, reaching 400 rpm for drills with a thickness of 13 mm or more.
When making a through hole, pay particular attention to the final drilling phase.
The drill can be caught by the side incisors on the burr formed at the outlet of the hole, which is fraught with a sudden blockage of the drill or even a fracture.
Always accompany the completion of the drilling process with less pressure on the tool.
If it is necessary to make a hole with a large diameter, first pre-drill using a drill with a diameter of 3 to 5 mm.
Then drill it with an 8 mm drill and only after that, crest a drill of the desired diameter in the chuck of an electric drill.
This approach will provide more efficient and faster metal cutting, reducing the likelihood of skewing.