Turning tools belonging to a single front , turning work because of different physical shape and have a lot of style , but the name and function of each part of it is the same . A good turning must have a good handle rigid and sharp blade into two parts . Turning angle of the blade , turning directly affect the effectiveness of different materials and turning the workpiece material , the angle of the blade is not the same . There are four important tool lathe car angle , that is, before clearance angle , side clearance angle , bevel and the edge bevel. 1 ) pre- clearance angle From the nose down to the tilt angle of the knife before the clearance angle , clearance angle due to the lower front , face and nose have formed a space, so that the cutting action focused on the nose . If this angle is too small , the friction between the tool surface , and produce a rough surface , the angle is too large, the tool is easy to tremor , the light can not be broken so that the nose system . Mounted on the front with a clearance angle of inclination of the knife turning mill , the need to consider the knife tilt angle. Between about 8 to 10 degrees angle of this high-speed steel tool , carbide turning tool is between 6-8 degrees. 2 ) side clearance angle Since the side cutting edge of the knife into the knife edge inclination angle of the clearance angle . Side clearance angle to make things work surface and knife side to form a space so focused on the cutting edge of the cutting action to improve cutting efficiency. This high-speed steel turning angle of between about 10 to 12 degrees. 3 ) After the bevel From the top surface of the knife holder from the nose to the angle of inclination of the bevel. This angle is mainly to reduce the boot chip and chip resistance. General metal cutting , high speed steel tool is generally 8 to 16 degrees, while the carbide turning negative or zero inclination . 4 ) beveled edge Since the knife cutting edge is inclined from the top surface side to the other , the inclined surface and the horizontal plane of the edge bevel angle . This angle is the angle of the chips to work things out , so that chip easily and get effective turning. General metal cutting , high speed steel tool this angle of about 10 to 14 degrees, while the carbide turning positive inclination can also be negative inclination. 5 ) knife angle end The angle of the blade and the handle perpendicular to the front . The effect of this is to keep the blade angle of the front and there is a gap between the workpiece and the workpiece to avoid friction or abrasion blade surface has been processed . 6 ) cut corners The angle of the blade and the handle perpendicular to the front , and its role as a change in the thickness of the shear layer. Meanwhile cut corners can change the turning direction of the force , reduce feed resistance, increased tool life , it is generally roughing , cutting corners to high turning should adopt in order to reduce feed resistance , increase the cutting speed. 7 ) nose radius The highest point of the knife-edge of the blade radius . Tool nose radius strength, depth of cut for a large , but easy to produce high-frequency vibration.