Internal threads are produced by thread cutting by using taps. The workpiece surfaces are processed by means of bores.
- Work is made in the chuck.
- The workpieces are clamped in the extended chuck jaws in order to guarantee true running and top surface quality as the parts have generally already been processed.
- The tap wrench is positioned on the square of the tap.
- The tap is positioned by means of the tailstock tip which is aligned to the centring of the tap.
Figure 18. Positioning the tap
1 tap, 2 tap wrench, 3 tailstock quill, 4 workpiece
- The tap wrench holder is positioned on a surface clamped into the tool holder.
- Generally speaking, the machine tap is used (economical mode of operation).
- Turn back the tap several times to remove the chips and clean the chip grooves.
- Ensure proper cooling and lubrication.
- Turn back the tap by hand upon completing the work sequence.
- The thread is checked by means of a thread ring mandrel.
Figure 19. Normal thread ring mandrel
1 thread mandrel for minor diameter
What must be heeded when thread cutting by