Drill bits for metal. What is a shank and what are they. They allow you to make holes of different depths.

Even if sharp edges or chips are used to animate gloves, this does not apply to rotating tools. Rotating drill or chips sticking to it can grip and wrap the glove. Strong drilling machines cannot be impressed with a gloved hand. Here, instead of an injured hand, an injury from an injury should be accepted. Gloves must not be worn on rotating machines.

Like a glove, the rotary drill can also grab, unwind and tear hair. Unfortunately, the exercise also does not distinguish between hair and scalp. The greatest danger, however, must be directed against the machine with its head. Therefore, wearing a head covering or protecting the hair is important for those with long hair.

Such serious accidents do not happen often. However, they show the dangers of a small rotating drill. However, the title has been deliberately omitted from the term "anchors" as there is more to it than just the seed.

Perforator with hammer and grain

On the table of the drilling machine, centering drills are already punched, with which it can be designed very precisely. The oldest and most familiar method for controlling a metal drill while setting it up is indentation. All it takes is grain and a hammer. However, how accurate this centering will depend on the grain design.

If the next position of the drill does not reach the tenth, a recess with a pencil or marker is sufficient for deepening. However, the grains attached to the markings can easily and inexplicably slip so that the next hole is not accurate. Here he can help, only very carefully, with a hammer on the grains to press, and then small grains indicate control. If this is not the case, the situation can be corrected in a second experiment. However, if the point of the grain is exactly on the crack, the tip of the grain can be easily reapplied to the grain, and the grain can be finished with a powerful hammer blow.

If the later surface is not visible or insignificant, the tear is recommended to be used with a stylus. It leaves a "scratch" in which a good grain tip will snap into place and therefore cannot slip. A sufficiently strong hammer blow and an accurate grain point is created.

Paradoxically, a drill can be used to establish centering so that no other exercise is performed. Such centering drills arose from the fact that it is hardly possible to manually grind them during the production process and then drill them with a machine. Hand grit is subject to some inaccuracy that must be manually compensated in each tool hole when drilling in the machine. It's tedious and costly to work time.

Large relief is provided by centering drills, which differ from conventional metal drills in several points. Most important point- material. The use is made of high speed steel, which is very hard and ensures that the center drill does not bend and thus work on the surface of the workpiece. The diameter of the front drill is very thin and requires only little pressure, which has a positive effect on the drilling result. After subsequent conical grinding, the centering hole can then be lowered and thus the diameter of the centering hole can be increased.

Narrow and deep centering ensures that the metal drill used later is guided for a long time and sagging is prevented. The disadvantage of centering drills is usually a thin diameter combined with a very hard and brittle material. Precise centering with a cordless drill or a hand drill often breaks the center drills. Therefore, they should be used mainly on stator drilling machines.

The thicker diameter allows for centering to the extent that the extra hole is further reduced. When drilling steel, large forces are generated in the direction of drilling and in the direction of rotation of the drill. These forces must counteract fixed systems.

The video is very clearly visible in the piercing, which occurs when the steel is not properly tensioned during drilling. As practical and fast as possible, the clamping arms also clamp, they only push the workpiece down onto the worktable and do not secure it against the side forces that occur during drilling.

The same applies when clamping in a vise. If the workpiece is held vertically between the clamping jaws and clamped tightly, there is always a risk that it will twist since there is no lateral support in the direction of rotation of the drill. It is safer to clamp the workpiece so that it has a fixed bearing in the direction of rotation of the drill.

Not ideal, but useful when drilling on a bench boring machine, can be a combination of stop and chuck. In this case, the stop already occupies part of the forces acting from the side. However, there is also a risk that the workpiece will kick off the stop and turn.

The ideal solution on a table or boring frame is machine powder. This holds the workpiece to the side and prevents twisting. In the same view, the blanks must be clamped in a hand screw. The drilling position - from top to bottom - is somewhat more uncomfortable, but provides the best support.

The right tool greatly affects the drilling result. "To a large extent" in this case means that it does not always have to be the most an expensive instrument. Also advantageous metal drills can provide excellent results with good polish and proper work drilling. However, a shorter lifetime is usually disadvantageous. If you can sharpen metal drill bits yourself, you'll be fine with better drill bits. Work obeys only more high effort because the drill needs to be re-sharpened more often.

An additional coating, such as cobalt, for example, can provide the best quality surfaces, stability and less adhesion of the chips. They do their job and are worth buying. If you don't have the ability to grind or grind the drills yourself, you can exchange dull or defective drills inexpensively.

Slightly more expensive but with higher wear resistance, these are coated twist drills. They are suitable for durable materials, as well as for soft aluminum, which fits less on the coated surface. For boreholes that are used frequently, customized but high quality drills can be used.

Right hand speed and cutting speed

Cutting speed is the speed at which the cutting edge touches the workpiece. In the case of a drill, it is taken extreme point cutting edge, as it provides top speed cutting. To determine the cutting speed or rotational speed, the circumference of the drill is first required. If the drill rotates one revolution, the outermost point of the cut has passed around the circumference after some time. This is the cutting speed. For drilling and other machining operations with rotating tools or workpieces, the following formula is obtained.