KEVOS® MAKEOS · Quality
Dovetail Inspection over Rods (Reading Limits, Accept or Reject)
What reading over (or between) rods should this dovetail give at its width limits, and does my measured reading pass?
Inspection of a male or female dovetail with two precision rods: the reading over or between the rods for the nominal width and at both width limits (as the dovetail measurement tool), the width worked back from your measured reading, whether the rods contact the flanks within the dovetail depth, and accept or reject against the width tolerance.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Dovetail type | choice | Male tongue (measure over rods) or female slot (measure between rods). |
| Dovetail angle (flank to base) | ° | Angle between the flank and the base. |
| Nominal width at the base corners | mm | Nominal width at the corners where the flanks meet the base. |
| Upper width deviation | mm | Upper deviation of the width. |
| Lower width deviation | mm | Lower deviation of the width. |
| Rod diameter | mm | Diameter of the two rods. |
| Dovetail depth | mm | Depth of the dovetail (the rods must touch the flanks within it). |
| Measured reading | mm | Micrometer reading over (or between) the rods. |
Method and formulas
- Rod factor k = 1 + cot(angle ÷ 2); reading = width + rod × k (male) or width − rod × k (female) (as the dovetail measurement tool).
- Width from a reading = reading − rod × k (male) or reading + rod × k (female).
- Rod contact height = (rod ÷ 2) cot(angle ÷ 2) sin(angle), which must be below the depth.
- Example: the reading should lie between 77.271 and 77.371 mm; 77.33 mm means a width of 50.009 mm.
Limitations
- Sharp corners at the base; corner radii or reliefs do not affect the rod reading but do affect the width definition.
- Rod diameter errors enter the result multiplied by the rod factor.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Inspect a dovetail slide or gib
- Put reading limits on a drawing
- Check whether the chosen rod size is suitable
Who it is for
- Inspectors
- Toolmakers
- Machinists
What you get
- Reading at nominal and at the width limits
- Width from the measured reading
- Rod contact and the decision
Interpreting the result
- Choose rods that touch the flanks near mid-depth: too small and burrs at the base interfere, too large and they ride over the top.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 682. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
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