Source: https://guthlabs.ai/docs/instruments/key-keyway-shear-bearing-stress-calculator/implementation/

instrument implementation / implementation-contract

# Key & Keyway Shear/Bearing Stress Calculator implementation

A source-bound implementation contract for Key & Keyway Shear/Bearing Stress Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-074

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification provides no safety-factor formula or allowable-strength input, so SF cannot be computed honestly. It also requires rejection of zero geometric dimensions; otherwise the stress formulas produce undefined division-by-zero results. Torque-sign handling is unspecified and can reverse both reported stresses.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "T": 100000,
    "T_unit": "N·mm",
    "d": 50,
    "w": 10,
    "h": 6,
    "L": 40,
    "length_unit": "mm"
  },
  "expected_outputs": {
    "tau_MPa": 10,
    "sigma_bearing_MPa": 33.3333333333,
    "SF": "undefined: no allowable-stress input or safety-factor formula"
  },
  "working": "τ = 2T/(d·w·L) = 2(100000)/(50·10·40) = 200000/20000 = 10 N/mm² = 10 MPa. σ_bearing = 4T/(d·h·L) = 4(100000)/(50·6·40) = 400000/12000 = 33.3333333333 N/mm² = 33.3333333333 MPa. SF cannot be calculated because no allowable stress or SF definition is supplied."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/key-keyway-shear-bearing-stress-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/key-keyway-shear-bearing-stress-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/key-keyway-shear-bearing-stress-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`