How to Select the Proper Cutting Tool for Lathe Operations

The selection of a cutting tool is  probably the most important decision of  machinists can make we're going to cover  some of the basics but I urge everyone  that intends to use a lathe to learn as  much about cutting tools as possible,they're the key to the quality of your  work lathe tools are made of many  different types of materials in many  sizes and styles.

The three types we're  using today are from the left high speed  steel tools carbide tip tools and on the  right carbide insert tools high speed  steel tools can be used for many turning  operations on all but the toughest  alloys the tools are sold as blanks in  many sizes and grades the machinist  grinds the point of the tool depending  on the type of metal he's cutting and  the type of turning operation he intends  to do a good machinist handbook will  give you the standard guidelines for  grinding high speed steel tools the  cutting edge of a carbide tip tool is  braised to the end of a steel shank.

The shape of the cutting edge its profile  and cutting angles are manufactured into  the tool a little clean-up on a green  wheel a silicon carbide grinding wheel  and the tool is ready to go cemented  carbide will handle much more heat than  high speed steel so carbide tools are  able to cut tougher metals and cut at  higher speeds cemented carbide is also  used to make small inserts that are  clamped to a tool shank this style  insert is manufactured with a cutting  edge on each of its three sides.

After an  edge is dulled the insert can be  unclamped and rotated to the next side  after all the edges have dulled the  insert is thrown away and replaced by a  new one although this type of cutting  tool was designed for the demands of  high production work it's really a great  tool for the beginner because it allows  even the person with little or no tool  sharpening experience the ability to  easily maintain a properly formed sharp  tool no matter what type of material the  cutting tool is made of it's the shape  of the tool that determines how it can  be used the profile of the tools point.

Determines the type of cut the tool is  designed to make  the location of the cutting edge on the  point of the tool determines the  direction in which the tool will cut  turning and facing tools are either  right or left hand tools depending on  which side of the tool shank the cutting  edge is ground right hand tools cut from  right to left  because the cutting edge is on the left  side of the tools point facing from the  center of a part to the outer edge  cutting right to left requires a right  hand facing tool left hand turning and  facing tools cut from left to right  cutting away from the headstock in a  turning operation or from the outer edge  to the center in a facing operation.

The  cutting edges on these tools are on the  right side of the tools point sending a  tool straight into a workpiece is called  a plunge cut this type of cut requires a  tool that has the cutting edge square of  the nose of the tool here we're using a  high speed steel cutoff blade and holder  the position of the cutting tool in the  tool holder is very important tools  should always be placed as far into the  tool holder as possible to give the  cutting edge adequate support and to  reduce the possibility of the tool  vibrating in the case of a boring tool.

Only the lengths needed to clear the  hole should extend out beyond the tool  holder the height of the tool should be  set to match the center of the lathe  axis a lathe center placed in the  tailstock can be used as a gauge to set  the height on this tool holder shims and  spacers are used to raise the tool the  tailstock is also used as a tool holder  for drilling reaming countersinking and  thread tapping operations on the lathe....