Turning is a metal cutting process uses a single-point tool to produce cylindrical surfaces oriented primarily parallel to the workpiece axis, while the tool is fed into the part radially, axially or both ways simultaneously. Different tool holder styles and insert types allows turning, facing, grooving, threading, and more turning operations, here is a basic guide for setting up a cutting tool on the lathe to ensure a part be turned properly.

1. Turn off the lathe machine, prepare a simple metallic ruler 

2. Mount a cutting tool onto the tool holder or tool post securely and set the holder perpendicular to the part.

3. Load your cylindrical part in the chuck of a lathe, when you tighten the chuck, rotate the part with your hand lightly, until it can’t move anymore, to center the turning part.

4. Make the lathe carriage close to chuck end and use cross feed wheel move the tool towards the lathe part, get the ruler pinched between the cutter and surface of the part tightly.

5. Observe whether the ruler is completely vertical, if the ruler is vertical, the tool height is set correctly, you should set tight the locking nut of the adjusting knurled wheel to keep the setting; if the ruler is tilting to the right or left, then the cutter is placed too low or too high, the tip of the lathe cutting tool is not in line with the center of the part. Release tool post cam and adjust the height wheel on the tool post to get it to the right height.

6. Remove the cutter and install it again longitudinally along the lathe axis, take the first trial cut to check if the tool is set at the right height. The proper setup will leave a smooth facing cut, while if the tool is not in the exact center position, there will be a little nib on the component.

7. If you need to turn a part along the axis, take out the tool and set it up again perpendicular to the part. Do this for all the turning cutting tools that you plan to use it turning your part or change the tool.