Stag Calculator

Mill · Lathe · Standards
Results
Results
Results
Suggested surface speeds (SFM) by material and tool. Use the lower end of the range for tougher cuts (deeper DOC, harder grade, less rigid setup). Use chip-load suggestions from tool maker — these are speeds only.
Spindle/drive efficiency factor (0.80 typical)
Results
75% is the standard machine-tap target; 60% for hand tapping in tough metals
Results
Xi = Cx + R·cos(θ₀ + i·360°/N)
Yi = Cy + R·sin(θ₀ + i·360°/N)
Coordinates
Right triangle. a = side opposite angle A, b = side adjacent to A, c = hypotenuse. Angle B = 90° − A.
Results
Stack Height = Bar Length × sin(Angle)
Stack gage blocks at one end of the sine bar/plate to tip the work to the desired angle.
Common bars: 5″, 10″ / 100, 125, 250 mm
Results
Theoretical Ra ≈ Feed² / (32 × Nose Radius)
Actual finish typically 1.5–2× theoretical. For finer Ra: increase nose radius, decrease feed, increase rigidity.
Results
Point Depth = (D/2) / tan(Angle/2)
Total Z-clear depth = target hole depth + point depth (so the full diameter clears).
118° standard HSS · 135° split-point / cobalt · 140° hard materials · 90° center-drill
Results
Std (pt/hr) = (60 / Cycle Time) × Efficiency
Hrs Earned = Parts Run / Std
% Std = Hrs Earned / Hrs Run
:
Minutes : Seconds
Allowance for setup, tool changes, breaks (0.80 = 80%)
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Results
Results