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metal drill bits

metal drill bits

Metal drill bits are specially designed bits for boring holes into various kinds of metal.
Metal drill bits can be used for just about every given purpose.
Metal drill bits are very versatile as there are different styles.

"Metal Drill Bits"

Twist the difference between the standard and the standard group and how to use the drill

 Diamond grinding group that is behind the metal drill bits   on alveolar symmetrical crescent-shaped grooves milled to form a concave arc edge , the cutting edge is divided into three main sections, namely the outer edge , circular blade , the blade ; mill hand when alveolar take the drill bit by the wheel fillets, roughly at the level of the center point of grinding wheel surface. The outer edge being substantially flat , beveled edge in order to ensure proper horizontal and lateral angle of the point B is positive . And to the side of the bit axis and the wheel angle of 55 °.
 When sharpening the drill tail depressed, an arc with the horizontal angle αk after the start sharpening , drill feed forward slow and steady , grind behind the alveolar form circular blade , ensuring radius R and the outer edge length L. If the wheel is smaller than the fillet radius R values ​​required for the drill to be in the horizontal plane with a slight swing pan to obtain the required value of R
  When sharpening when alveolar drill must not grind the outer edge and as bobbing up and down in a vertical plane or axis of rotation around the drill bit , otherwise it becomes S -shaped chisel . Chisel edge angle becomes smaller, and also difficult to control the shape of a circular arc symmetrical . The key is to ensure symmetrical inverted 180 ° drill grinding months back when the other side of the alveolar , attention should change their spatial location in order to ensure the arc , terrible sharp symmetrical
The difference between the standard and the standard twist drill group
Standard twist drilling group compared with the standard , mainly for the following points : ( 1 ) the rake angle is smaller the closer the standard twist center of the horizontal edge of the rake angle is negative , the drilling resistance , not easy to cut. Standard group drill and grind the edge of the arc edge , the front edge of the corner arc BC segment increased an average 10 °, the average increase in the blade segment CD 25 °, so the drilling group with a more sharp cutting performance. ( 2 ) standard twist drill horizontal blade was too blunt , too wide , resulting in a large drilling force ( especially the axial force ) , the standard group will cross sharpening tip drill , grind narrow , so terrible at the sharp, cutting can play effect. In order to protect the terrible tip, tip height h try again grind lower , and appropriately increase the angle of the front edge (2φ '). ( 3 ) When the drill diameter greater than 15mm, standard drilling group on one side of the outer edge grind of flutes , the chips can automatically break and smooth discharge , and contribute to cutting fluid inflow , thus reducing the cutting force and cutting heat .

How to change drill bits
Hand holding  metal drill bits small black circle, the other hand grasp at which large, twist the opposite direction, will be able to drill clamped or released. The black circle on the handle button is used to protect. Which is used to tune that speed. If this is the special wrench to unscrew the black. If you just kind of what I call that method.
Which button is not used to protect the black circle, is the self-locking button. Is used to keep drill actuated state, using the method hold switch, and then press the auto-lock button to lock the switch, allowing drill kept turning off, hold down the switch, then release the locking button on the line. This instruction manual inside the drill.
Drill sharpening process on the impact of design
Hollow drill bit less dosage, processing small quantities, so the design should consider the drill process issues, as far as common machining equipment and tools used to achieve processing and grinding.
The rake chip out, so a direct impact on the shape of the rake face and chip performance chip shape. Used chips in the process of being squeezed and friction of the rake face, and further deformation. The maximum degree of deformation of the base metal chips and to slip along the rake face, the chips bottom length is longer, thereby forming a variety of crimp shape. When using a hollow  core drills bit and hope the chips into crumbs or ribbon cuttings, in order to facilitate chip removal. For ease of machining and grinding, must be designed for flat rake face, without chip breaking groove. Rake in use does not require re-grinding.
Hollow drill flank is most likely to re-grinding of the face, but also the fastest surface wear, so hollow drill flank grinding sharpening is achieved.
Deputy Vice flank divided into inner and outer flank minor flank. Heavy grinding perspective, re-grinding inner and outer flanks not easy to achieve, so minor flank shall be designed for a throwaway form.
Based on the above analysis, the hollow drill blade is designed in the form shown in Figure 1. Processing Practice has proved that the design can meet the requirements and tool regrinding requirements.
With the use of optional drill
1, the current classification of common auger drill
Common auger drill with auger, auger bucket, drum core drills , pedestal drill, impact drill, punch caught cone drill and hydraulic grabs, following a brief introduction by category.
1,1 auger
(1) Cone: Double twin screw, suitable for hard rock. Double monospiro for weathered bedrock, gravel, ice-rich permafrost and so on. These drill fitted with a variety of cutter, through tooth, pitch, helix angle changes can be derived from many types of drills.
(2) vertical auger:
a, bucket teeth straight screw
Double-headed screw, suitable for sand, cemented poor small-diameter gravel; stud monospiro for sand, soil; single head single spiral suitable for large diameter pebbles cemented poor, clay and hard clay .
b, cutter straight screw: a double spiral, three and four snails snails for so hard bedrock or gravel.
1,2 rotary drill bucket
Teeth can be divided by the installed cutter drill drill bucket and bucket teeth bucket; plate number can be divided by a double bottom and single bottom bucket bucket; can be divided according to the number of open double doors and single door bucket bucket; press the barrel taper can be divided into straight taper barrel drill bucket and bucket drill bucket; plate shape can be divided according to the lower bottom of the pot bottom drill bucket drill bucket peace. Above structure combined with each other, coupled with or without vents, door body changes, you can combine dozens of rotary drilling bucket. Generally double bottom drilling bucket for a wide range of formations, applies only to single-bottom soil viscous strong, two-door drill bucket for a wide range of formations, single door only for large diameter drill bucket of gravel and hard clay.
1,3 drum core bits
Currently there are two common: tube cutter drill (for medium hard rock and gravel), cone cylinder drill (for hard bedrock and boulders). In the drum coring drill bit in two categories, and coring device with and without coring device of the points, depending on the difficulty of coring. Because cone core drill is mainly used for hard rock drilling, and drill annular area, if the conditions, they can still pass on the part of the drill to install reverse circulation drilling to improve drilling efficiency.
Drill 1,4 belled
In the pile diameter does not increase without increasing the depth of the pile on the basis, in order to improve the bearing capacity of single pile, the design sector is often achieved through the pedestal pile, rotary drilling rig construction is reamed construction without any change can be simply expanded selection bottom drill can be. Belled drill bit used to mechanically based, such drills are relatively simple to use and maintain, with upper and lower open open, the opening of the four-bar linkage mechanism is generally used for soil, strong winds, weathered even hard rock formations. As a non-circulation drilling auger drilling, completion reamed barrel with slag slag can be.
1,5 impact drill, punch caught cone drill bit
In drilling large diameter pebbles, boulders and hard bedrock, use an impact drill, punch caught cone drill bit with Rotary Drilling particularly effective is through the use of this type of drill auger auxiliary hook hanging to the job, because only a shock effect, so we have the freedom to put requires auxiliary hook rope functional effects can be better.
1,6 hydraulic grab
Currently continuous wall and cut-off wall construction work increasingly see more, if you can make a little change rotary drilling rig operations, hydraulic grab the opening and closing is hydraulically driven, hydraulic grab only one cylinder, so only need access to two tubing, a control valve can be.
2, according to the geological conditions selected drill
Rotary drilling rig main function is to form a hole in the ground slot, the work object is rocky, since the construction of the pile hole depth shallower rocks through tectonic movement, mechanical and chemical nature of the role, structure, grain size, porosity, cementation condition , occurrence, strength and other complex changes took place, coupled with our vast pieces of the original, so the work of rotary drilling rig is particularly complex objects. Summed up in the following categories.
Press the lithology of (common) of shale, sandstone, limestone, granite, etc.; press the genesis of magmatic rocks, sedimentary, and metamorphic; divided by rugged mechanical properties, plasticity and loose. So how to choose based on stratigraphy drill it? Following classification introduced.
(1) Clay: use single bottom of rotary drilling bucket, if the diameter is too small can be used with two dump bucket or bucket drill plate.
(2) slurries, viscous soil is not strong, sand, smaller particle size less cemented gravel layer, can be equipped with double bottom drilling drill bucket.
(3) Hard clay: use a single port into the soil (single double bottom can) auger drilling bucket, bucket teeth or straight screw.
(4) the permafrost: ice bucket teeth available less straight auger hopper and auger drilling bucket, containing a large quantity of available cone ice auger, a description that auger for soil (except mud outside) are effective, but there must be the case in the absence of groundwater use, in order to avoid pumping action caused stuck. (5) cemented gravel and weathered rock: the need to drill and screw with conical double bottom auger drilling bucket (larger particle size with a single port, dual port with a small particle size)
(6) Stroke bedrock: with a cutter drum coring drill - conical spiral drill - double bottom bucket auger drilling or cutting tooth straight auger - double bottom auger drilling bucket.
(7) weathered bedrock: Drum coring drill with cone - Conical spiral drill - double bottom bucket auger drilling larger diameter should be taken if the grading drilling technology.
3, according to the rotary drilling rig function to select drill
If the rotary drilling rig has made a continuous function, can be equipped with hydraulic grab or continuous milling wheel construction. If the auxiliary winch rope with automatic release function, optional impact drill and drilling large diameter drill punch caught pebbles or boulders. If equipped with a gas chamber and faucets can be liquid drilling. If equipped with dual power head or rub into the casing pipe drilling machine can be, which is to solve the flow of sand, crushed gravel, silt layer effective construction method.