Twist drill and three-flute drill
麻花钻头 Twist drill: A tool for drilling round holes in workpieces by rotating and cutting relative to its fixed axis. It is named for its resemblance a pretzel due to its spiral flute. It can be clamped in hand-held drilling tools or drill presses, milling machines, lathes, and even centers for use. 三斜面钻头 Three-sided drill: Usually made of alloy, it is suitable for use in machining centers. It can reduce the friction coefficient, has wide chip evacuation groove design, and offers high precision. Processing impact The diameter of the twist drill is limited by the hole diameter, the rigidity of the bit is low, and the axis of the hole is prone to deviation. The cross-edge makes it difficult to center, increases axial resistance, and makes the drill prone to swinging, resulting in larger positional errors in the drilled hole. The front and back surfaces of the twist drill are both curved, with different rake and clearance along the main cutting edge. The cutting conditions are poor, the cutting speed distribution along the cutting edge is unreasonable, and the cutting speed at the weakest part of tool is the highest, leading to severe wear and low hole accuracy. The entire main cutting edge of the drill bit participates in cutting, with unequal cutting speeds at points along the edge, easily forming spiral chips, making chip evacuation difficult. It often scratches the hole wall, resulting in low surface roughness after processing. The drill has poor positioning accuracy, is difficult to grind symmetrically, and hand grinding poses certain risks, requiring a high level of technical skill from the operator. Three drills are not suitable for manual processing and can affect dimensional accuracy. Solution Portable drill bit grinder, equipped with diamond grinding wheels made in Taiwan, ensures accuracy and durability. It can grind the drill bit's apex angle ( angle), front cutting edge (positive rake angle), flute (back angle), and the size of the central cross-edge can be easily adjusted. It can grind the drill bit tip angle (apex angle), the front cutting edge (positive rake angle), and the chip evacuation groove (negative angle). It can replace the center drill for more precise positioning, easier chip evacuation, and easier drilling. For three-slope drills, internal and external cooling drills and powder metallurgy drills.