RPM Formula:
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Definition: This calculator determines the optimal rotational speed (RPM) for thread cutting based on cutting speed and thread diameter.
Purpose: It helps machinists and engineers calculate the proper spindle speed for thread cutting operations to ensure quality and tool longevity.
The calculator uses the formula:
Where:
Explanation: The formula converts cutting speed (linear velocity) to rotational speed by accounting for the circumference of the thread.
Details: Proper RPM calculation ensures optimal cutting conditions, prevents tool damage, and produces high-quality threads with the right surface finish.
Tips: Enter the cutting speed in m/min and thread diameter in meters. All values must be > 0.
Q1: What is a typical cutting speed for threading?
A: Cutting speeds vary by material: 30-60 m/min for steel, 60-120 m/min for aluminum, and 15-30 m/min for stainless steel.
Q2: How do I convert diameter from mm to meters?
A: Divide mm by 1000 (e.g., 10mm = 0.01m).
Q3: Does this work for both internal and external threads?
A: Yes, the formula applies to both, though internal threads may require slower speeds due to tool rigidity.
Q4: Should I adjust RPM for different thread pitches?
A: The basic formula doesn't account for pitch, but finer pitches may require speed reduction for better control.
Q5: What if my machine can't reach the calculated RPM?
A: Use the nearest lower speed setting and adjust feed rate accordingly.