Drill bits come in a wide range of shapes and sizes, and are available in a variety of materials and coatings. Most tooling and machining operations have a drill bit that’s designed specifically for the task. Here’s a quick overview of several types of drill bits, materials and design types.
Drill bits are the special rotating tools that have cutting capacity at the top. Generally, drill bits are made from carbon steel (SK), HHS (SKH2, SKH3), etc, and then by milling machining or quenching after rolling, the final step is the grinding after tempering heat treatment. Drill bits are used for machining metals or other materials. Drill bits have a wide useful, such as drilling machine, lathe machine, milling machine and power drill, etc.
First: Preparation Before Grinding
A: Assembly of Drill Bit and Fixture
- Checking the diameter of drill bit shank, then select the suitable collet chuck and cutting sets.
- Insert the collet chuck into the fixture and lock the nut.
- Put the drill bit into the collet chuck, and keep 35~50mm out of the collet chuck.
- Adjust the scale to suit the outer diameter of the drill bit, and adjust the angle of point angle.
Attention: Keep some margin for adjusting before locking the chuck sets.
Definition of Ni Zhifu Ordinary Twist Drill Bit: Based on standard twist drill that the cutting part is grinded onto a special shaped drill bit. The standard twist drill consist of two major cutting lips (major cutting edges) and a chisel edge. The most fatal weakness is that the negative front angle of chisel edge and dead center are larger, led to the cutting conditions are unfavorable. Ni Zhifu Ordinary Twist Drill Bit is that grinding two symmetrical crescent grooves based on standard twist drill, forming arc blade, and then sharpening two inner straight edges on the chisel edge and dead center. After that, with the chisel edge and original two straight edges, making the standard twist drill into “Three knife-points and seven knife-edges” that is the Ni Zhifu Ordinary Twist Drill Bit.Continue reading
In actual work, we will encounter some special machining phenomenon, such as machining a larger diameter hole, or bottom of hole should beflat. Today, here we introduce reaming and countersinking, let’s go.
Carpenter Drill Bit: The carpenter drill bit for drilling wood there has larger amount of stock removal. Generally, it is made of ordinary carbon steel, the manufacturing process of the carpenter drill is simple, such as forging, stamping, grinding, etc.
Metal Drill Bit: Generally, the metal drill bit is made of alloy of hardness or HHS(high-speed steel), etc. The metal drill bit is cast and molded, after that to be grinded by grinding wheel on the grinding machine. Its manufacturing process is more complicated than carpenter drill bit.
The drilling machining is one of the most difficult machiningin metal machining, cause of that:
1th: Holesmachiningare the forming machining, the design of drill bit is good or not that directlyeffects on the accuracyof bore diameter.
2nd: The blade is in the hole, cooling is difficult.Continue reading
The drill bits are special cutters that are used to drill through holes or blind holes in solid materials, and also reaming holes in existing holes. The most commonly used drills are twist drill, flat drill, centre drill, deep-hole drill and trepanning drill. Although reaming drill and M drill can’t be drilled holes in solid material, but they are also customary to put them in the drill bit classes.