The hand of the latheДЇigure I-79 The change in chip width with an increase of theВ side cutting edge angle. Left-hand toolsВ are shaped just the opposite of right-hand tools (Figure I-80).В The right-hand tool has the cutting edge on the left side andВ cuts to the left or toward the headstock. When the purposeВ for the rake and relief angles on a tool is clearly understood,В then a tool suitable to the job may be ground. Grinding a tool provides both a sharp cutting edge andВ the shape needed for the cutting operation. The smallest nose radius that will give theВ desired finish should be used. The nose radius will vary according to the finishВ required. Tools used for squaringВ shoulders or for other light machining can have anglesВ from 5 to 32 degrees, depending on the application.Д§. The side cutting edge angle (SCEA) may vary considerably.В For roughing, it should be almost square to theВ work, usually about 5 degrees. The side relief angle provides for cutting action byВ allowing the tool to feed into the work material.Д¦. The end relief angle prevents the front edge of the toolВ from rubbing on the work.ДҐ. The side rake directs the chip flow away from theВ point of cut and provides for a keen cutting edge.Д¤. Back rake is important to smooth chip flow, which isВ needed for a uniform chip and a good finish, especiallyВ in soft materials.ДЈ. The tool shank is that part held by the toolholder.Дў. The terms and definitions follow (theВ angles given are only examples and can vary according to theВ application).ДЎ. High-speed tools have been largely replaced inВ production machining by carbide tools (Figure I-77)В and angles of the tool according to a commonly used industrialВ toolВ signature. High-speed steel is used for many tools, as it fulfillsВ these requirements and is easily shaped by grinding.ДЇor thisВ reason it is used in this unit to demonstrate tool geometry (seeВ Table I-1). This tool must be hardВ and should not lose its hardness from the heat generated byВ machining. On a lathe, metal is removed from a workpiece by turningВ it against a single-point cutting tool.

Radius cut lathe cutting tools