Question

It is required to cut a single-start thread of 2 mm pitch in a lathe machine with a single-start lead screw of 4 mm pitch. For one revolution of the workpiece, the number of revolutions of the lead screw is \(\underline{\hspace{2cm}}\) (round off to two decimal places).

Hint:

The ratio of thread pitch to lead-screw pitch directly gives the required lead-screw revolutions for thread cutting.

Answer 1

Correct Answer: 0.4 - 0.6

To generate a thread of pitch 2 mm, the tool must advance 2 mm per revolution of the workpiece. The lead screw pitch is: \[ P_{\text{lead}} = 4\ \text{mm/rev}. \] Let \(N\) = revolutions of lead screw per one revolution of workpiece. Then: \[ N \times 4 = 2 \] \[ N = \frac{2}{4} = 0.50. \] Rounded to two decimal places: \[ 0.50. \]