A twist drill is a tool that drills a round hole of a work piece by rotating cutting relative to a fixed axis. It is named after its spiral flute with a spiral shape resembling a twist. Spiral grooves have 2 grooves, 3 grooves or more grooves, but 2 grooves are the most common. Twist drills can be clamped on manual, electric hand-held drilling tools or drilling machines, milling machines, lathes and even machining centers. The bit material is generally high-speed tool steel or cemented carbide. So, what brand of twist drill is good? What are the specifications of twist drill bits ? For friends who have needs in this regard, it is one of the topics worth paying attention to. Don't worry, what I want to introduce to you today is the specifications of the twist drill bit and what brand of twist drill bit is good. I hope to help friends who have needs in this regard!
Disadvantages of twist drills
Although the geometry of the twist drill is more reasonable than the flat drill, it still has the following disadvantages:
(1) The value of the rake angle at each point on the main cutting edge of the standard twist drill is too different inside and outside. The rake angle of the main cutting edge at the outer edge of the drill bit is about + 30 °; and close to the drill core, the rake angle is about -30 °, and the rake angle near the drill core is too small, causing large chip deformation and high cutting resistance; and near the outer edge When the rake angle is too large, the cutting edge strength is often insufficient when machining hard materials.
(2) The lateral blade is too long, and the rake angle of the lateral blade is a large negative value, ranging from -5 4 ° to -6 0 °, which will generate a large axial force.
(3) Compared with other types of cutting tools, the main cutting edge of a standard twist drill is very long, which is not conducive to chip separation and chip breaking.
(4) The secondary clearance angle of the secondary cutting edge at the land is zero, which causes increased friction between the secondary flank face and the hole wall, the cutting temperature rises, the abrasion at the corner of the outer edge of the drill bit is large, and the roughness of the processed surface deteriorates .
Twist drill specifications
The use of twist drills is one of the most widely used drill bits in industrial manufacturing. We generally use twist drills. The length-to-diameter ratio of the drill bit needs to be calculated when the craftsman selects the most suitable drill type for a specific hole machining task. Diameter ratio. The aspect ratio is the ratio of the depth of the processed hole to the diameter of the drill bit. For example, if the diameter of the drill bit is 12.7 mm and the depth of the hole to be processed is 38.1 mm, the aspect ratio is 3: 1. When the length-diameter ratio is about 4: 1 or less, the chip flutes of most standard twist drills can smoothly discharge the chips removed by the cutting edges of the drill bits. When the length-to-diameter ratio exceeds the above range, a specially designed deep hole drill is needed to achieve effective processing. The standard products of twist drills adopt national standards and equivalently adopt international standards. Once the length-to-diameter ratio of the processed hole is greater than 4: 1, it is difficult for the standard twist drill to push the chip away from the cutting area and discharge it out of the hole. The chip will soon block the chip flute, and it is necessary to stop drilling and remove the hole from the hole Withdraw the drill bit, clear the chips in the chip flute, and then drill down to continue cutting. The above operation needs to be repeated many times to process the required hole depth. This drilling method is usually called the "pecking" method. Using "pecking" method to process deep holes will shorten tool life, reduce machining efficiency, and affect the quality of processed holes. Each time the drill bit is withdrawn from the hole, and when it is cleared and reinserted into the hole, it may deviate from the center line of the hole, thereby making the hole diameter larger than the specified dimensional tolerance range. In order to solve the problem of deep hole machining, in recent years, the drill manufacturer has developed two new types of deep hole machining drills-ordinary parabolic drills and wide blade parabolic drills.
What brand of twist drill is good
1. Far East TDC has achieved overseas mergers and acquisitions in the hardware industry enterprises, large twist drill manufacturers, industry leaders, Dalian Far East Tools Co., Ltd.
2. Tiangong TG high-tech enterprise, one of the leading high-speed steel / cutting tool production bases, a large twist drill manufacturer, Jiangsu Tiangong Tools Co., Ltd.
3. Feida FEIDA is one of the world's largest high-speed tool steel manufacturers, high-tech enterprises, international enterprise groups, Jiangsu Feida Drill Bit Co., Ltd.
4. Shanggong was founded in 1949, one of the most influential brands in the domestic cutting tool industry, Shanghai famous brand products, Shanghai Tool Factory Co., Ltd.
5.BOSCH power tools began in Germany in 1886, the world's brand, the world's leading manufacturer of power tools, industry influence brand, Bosch Power Tools (China) Co., Ltd.
6.Lianhuan Links is one of the largest precision tool manufacturing enterprises in China, a leader in the Chinese tool industry, Harbin Measuring Tool Group Co., Ltd.
7. Fang Dawang is a well-known enterprise in the national drill (construction) industrial base, ten hemp flower drill brand, well-known domestic hardware tool industry brand, China Fangda Holdings Co., Ltd.
8. Sichuan brand was founded in 1956, a key production enterprise of measuring tools, a high-tech enterprise, Chengdu Chengliang Tool Group Co., Ltd.
9.Black & Decker Black and Decker originated in the United States in 1910, the world's most famous electrician tools / household appliances production brand, the world's first gun-type portable electric drill, Stanley Black
10. One of the largest domestic precision tool / CNC tool production bases in Ha Yigong, a major backbone enterprise in China's key equipment industry, Harbin First Tool Manufacturing Co., Ltd.
The ten hemp flower diamond brands are all well-known twist diamond brands on the market. Although the price may be higher, the service life is relatively longer, and the materials are also better. You can choose from them. If your economic situation is more general, you can also consider choosing the well-known twist drill brands on the market: Heyi Gong, DLTC, Baili Kugel, Zhengbang, GUHRING Cobalt Collar, Dangong, although not as high as the top ten twist drills Knowledge, but also safe and reliable.
Grinding method of twist drill
1. "The edge of the blade is balanced against the wheel."
This is the first step in the relative position of the drill bit and the grinding wheel. Often, some students lean on the grinding wheel and start sharpening before the edge is evened out. This must be bad. The "cutting edge" here is the main cutting edge, and "swinging" means that the main cutting edge of the sharpened portion is in a horizontal position. "Wheel surface" refers to the surface of the grinding wheel. "Relying" means slowly moving closer. At this time, the drill bit cannot contact the grinding wheel.
2. "The drill shaft obliquely releases the angle of attack."
This refers to the positional relationship between the axis of the drill bit and the surface of the grinding wheel. The "angle of attack" is half of the apex angle of 118 ° ± 2o, which is about 60 °. This position is very important, which directly affects the size of the apex angle of the drill bit, the shape of the main cutting edge and the angle of the transverse edge. It is necessary to remind students to remember the angle of 60 ° in a 30 °, 60 °, 90 ° set square, which is easy for students to master. Both recipe one and recipe two refer to the relative position of the drill bit before sharpening. Both must be taken into consideration. Do not neglect to set the bevel in order to level the cutting edge, or neglect to level the cutting edge in order to set the inclined axis. In actual operation, these errors are often very likely. At this time, the drill bit is ready to contact the grinding wheel when the position is correct.
3. "From the blade to the back grinding."
This refers to the sharp edge along the entire flank surface starting from the edge of the drill bit. This facilitates heat dissipation and sharpening. On the basis of stabilizing and consolidating formulas one and two, at this time, the drill bit can lightly contact the grinding wheel to carry out a small amount of sharpening. During sharpening, the uniformity of the spark should be observed, the pressure should be adjusted in time, and the cooling of the drill should be paid attention to. When re-sharpening after cooling, it is necessary to continue to set the position of the first and second formulas. This is often difficult to grasp in the beginning, and often changes the correctness of its position involuntarily.
4. "Don't tilt the tail up and down."
This action is also very important in the process of sharpening the drill bit. Some students often change the "swing up and down" to "turn up and down" during sharpening, which destroys the other main edge of the drill bit. At the same time, the tail of the drill cannot be higher than the horizontal centerline of the grinding wheel, otherwise the cutting edge will be blunt and cannot be cut.
Twist drill use and maintenance
1. When using the twist drill, first insert the bolt connector of the horizontal part into the orientation groove of the movable connection nut of the drill head bar, and tighten the connection nut counterclockwise to insert it into the predetermined drilling area and press it by hand to screw it clockwise In the soil, the drill hole is lifted upwards every 200-250 mm. (If it is too deep, it will be very laborious and inconvenient). Remove the spiral middle soil of the drill bit. This soil is the soil sample at a distance from the lot.
2. When reciprocating one by one to 1 meter, it is necessary to continue to drill deep. Unscrew the connecting nut of the connecting part of the drill part clockwise to remove the horizontal bar, and connect the bolt head part of the additional second section of the drill rod part to the drill part activity Tighten the connection nut in the clockwise direction of the connection screw, and then connect the crossbar component to the drill rod as above (1) and continue to work. Continue three, four, and five sections until the end of the work.
3. Twist drill pipe is made of seamless wall steel pipe, so it is not suitable for use in hard soil areas.
4. After each use, wash and dry it, and apply anti-rust grease to prevent rust.
Editor's summary: The above is a description of what brands of twist drills are commonly used, and hope to help friends who have needs in this regard! For more related information, please continue to follow our website, and more exciting content will be presented in the future. You can also go to Qijia Mall to buy more products you like!
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