Compare the crank angles used for working and return strokes in an ideal quick-return cycle. A separate clearance comparison uses an assumed 0.050 mm reference, which is not a universal production tolerance.
Whitworth Quick-return Interactive Calculator
Enter r/e and block clearance. Timing is ideal constant-speed angular arithmetic; lash margin is simply 0.050 mm minus the entered clearance.
Equation Used
- Entered r/e lies within the displayed range.
- Input angular speed is constant.
- Time ratio equals crank-sweep ratio.
- The clearance reference is fixed at 0.050 mm.
- Closure, stroke, loads, wear and safety are omitted.
Quick-Return Sweep and Clearance comparison
The timing result depends on r/e. The clearance result is a separate comparison with the assumed reference.
What This Calculator Represents
Ideal crank-angle timing and a separate comparison with an assumed clearance reference.
Timing and Clearance Calculations
cut=180+2alpha
return=180-2alpha
margin=0.050-c
Worked Scenario
At r/e=0.5, sweeps are 240 and 120 degrees for 2:1. At 0.050 mm clearance, fixed-reference margin is zero.
Assumptions and Limits
No stroke, closure, tolerance stack, wear, forces or safety calculation is included.
Frequently Asked Questions
Is 0.050 mm universal?
No.
Is negative margin failure?
Not by itself.
Is stroke solved?
No.
Is input speed needed?
Not for the ratio.
Are forces included?
No.
Can this set production tolerances?
No.
References
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