Among the elements that constitute a drill we find:
Total length of the bit: There are extra short, short, normal, long and extra long bits. The latter is customary to use with a bench drill for the purpose of drilling deep into a surface so that the bit does not damage or ruin the hole.
Cut Length: It is the maximum depth that can be drill with a wick y is defined by the useful length, which is determined by the extension of the propeller.
Cut Diameter: is the diameter of the hole obtained with the drill.
Cutting angle: The normal cutting angle on a drill It is 118º at the tip, but there are also drill bits 135º so that the more contact with the material, the wick self-centers and does not slip on the surface.
Shank diameter and shape: The handle of a drill can be cylindrical, triangular or conical. Thecylindrical handle It is the most common, but it should be noted that there is a subtype that is the reduced handle, which consists of a decrease in the size of the handle in drills whose diameter exceeds 10 mm or 13 mm, so that the drill can be used in chucks of the measures mentioned. Regarding the triangular handleIt is a bit with notches on the surface that are in contact with the chuck so that the tool does not slip; It is customary to make this modification in bits destined to pierce very hard metals, such as alloy steels, matrices, etc. Finally there are those of conical handle, which have the particularity of being positioned on a special chuck, they are usually used to drill deep holes and of significant thickness.
Helix angle: Depending on the material to be drilled, the wick it can have a particular angle to cut the chip and evacuate it. There are a number of letters to identify the application and angle of the bit: N is the propeller angle of 30º for general use, W corresponds to the 40º / 45º angle for machining Aluminum and long-chipping materials. The type H, is known as the slow helix, due to its long helical pitch at an angle of 15º / 20º, it is ideal for bronze and other materials whose chips are large. Finally, there is the propeller type S with an angle of 35º and highlighting at first glance the quality of having a dense groove for a quick removal of the shavings; this type is used for stainless steels.
Parts of a Drill Bit
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