03-22-2015, 05:46 PM
Hello Flosi,
The only limiting factors in threading with CNC is the tooling (need carbide) and the processing speed of the control. The second is the key to what speeds you can run because of the timing required to position the slides, execute the coordinated motion of Z axis with spindle rotation to get the right lead, retract X at the end of the cut, return in Z to the start point, lather , rinse, repeat.
When I first started using NC machines (paper tape Numerical Control) the threading speeds were "a few hundred rpm". Any faster would have the threading tool not in X position before the Z motion started and pulling out before Z axis had reached the programmed position. The CNC machines of a 1/2 dozen years ago could thread at 2000 to 2500 rpm successfully. New CNC machines (commercial, full blown CNC not a Sherline) can thread at twice those speeds.
You can find the limits of your individual machine by experimentation "in air" by just watching the position readouts. If the X axis starts retracting before the programmed Z position is reached, you must slow down the process.
Good luck,
Ken
The only limiting factors in threading with CNC is the tooling (need carbide) and the processing speed of the control. The second is the key to what speeds you can run because of the timing required to position the slides, execute the coordinated motion of Z axis with spindle rotation to get the right lead, retract X at the end of the cut, return in Z to the start point, lather , rinse, repeat.
When I first started using NC machines (paper tape Numerical Control) the threading speeds were "a few hundred rpm". Any faster would have the threading tool not in X position before the Z motion started and pulling out before Z axis had reached the programmed position. The CNC machines of a 1/2 dozen years ago could thread at 2000 to 2500 rpm successfully. New CNC machines (commercial, full blown CNC not a Sherline) can thread at twice those speeds.
You can find the limits of your individual machine by experimentation "in air" by just watching the position readouts. If the X axis starts retracting before the programmed Z position is reached, you must slow down the process.
Good luck,
Ken