A wafer-tumbler lock uses spring-biased flat wafers whose correct key positions clear the plug-to-shell boundary. This calculator is only a one-offset tolerance calculation.
Wafer Tumbler Lock Interactive Calculator
Enter a signed wafer-offset index and tolerance. Results are a one-dimensional comparison—not a key code, lock-opening guide, jam-angle prediction, torque model or security assessment.
Equation Used
- Only one signed offset and one positive tolerance are entered.
- Alignment error is the absolute offset magnitude.
- Margin is an arithmetic difference and tolerance used is a ratio.
- The angle-like score is zero within tolerance and 25 degrees per millimetre of absolute offset outside tolerance.
- Wafer count, key bitting, spring force, plug/shell geometry, clearances, friction, torque, wear, manufacturing uncertainty, lock operation and security resistance are omitted.
Wafer and Plug-to-Shell Boundary
U.S. Patent 6,959,569 describes wafer-shaped tumblers sliding in channels between a plug and shell; correct key positioning removes interference so the plug can rotate. This page does not model a specific lock or key.
What This Calculator Represents
Compare the magnitude of an entered offset with a chosen tolerance. The margin and percentage describe that comparison; the additional angle-like score follows the displayed arbitrary rule.
One-Offset Tolerance calculation
margin=T−|e|
used=100|e|/T
score=0 if |e|≤T; otherwise 25|e| degrees
The degree-valued score is heuristic and is not a physical jam angle.
Worked Comparison Example
For e=+0.20 mm and T=0.10 mm, error is 0.20 mm, margin is −0.10 mm, utilization is 200%, and the calculator's heuristic score is 5.0 degrees.
Assumptions and Limits
- Calculated: absolute offset, signed margin, tolerance utilization and an arbitrary illustrative score.
- Illustrated: one generic wafer crossing or clearing a boundary.
- Not calculated: a key, lock operation, interference force, torque, wear, tolerances across an assembly or security performance.
Frequently Asked Questions
Does the calculator reveal a key code?
No.
Is the angle score a physical wafer angle?
No.
What does negative margin mean?
The entered offset magnitude exceeds the entered tolerance.
Does offset sign affect the outputs?
Only the input display; the arithmetic uses absolute value.
Are spring force and torque included?
No.
Does this assess lock security?
No.
References
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