BIZOMAT MAKEOS · Quality
V-Groove Measurement over a Pin
How far should a gauge pin stand above the surface in this V-groove?
Height of a gauge pin above (or below) the top surface of a V-groove, the depth of the sharp V and the pin contact positions.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Included groove angle | ° | Included angle between the two flanks from the drawing. |
| Groove width at the top surface | mm | Width of the groove where the flanks meet the top surface (sharp-edge theoretical). |
| Pin diameter | mm | Measured diameter of the gauge pin. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Included groove angle
- What it is
- The included angle of the V-groove: the full angle between its two flanks, as given on the drawing.
- Units and format
- Enter a number in °: degrees of angle. The form accepts 1° to 179°. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 90° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Use the full included angle, not the half angle from the centre line.
What this means: Groove width at the top surface
- What it is
- The theoretical width of the groove at the top surface, where the two flanks would meet the surface with sharp edges.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Use the sharp-edge width; a chamfered or rounded edge measures wider than the value the formula needs.
What this means: Pin diameter
- What it is
- The actual diameter of the gauge pin laid in the groove, measured with a micrometer.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 10000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 6 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- If the pin is too large it rests on the groove edges instead of the flanks and the tool reports it.
Method and formulas
- Pin centre above the sharp V apex = (D ÷ 2) ÷ sin(β ÷ 2), where β is the included angle.
- Depth of the sharp V = (W ÷ 2) ÷ tan(β ÷ 2).
- Pin top above the surface = (D ÷ 2)(1 + 1 ÷ sin(β ÷ 2)) − depth.
- Example: a 90° groove 10 mm wide with a 6 mm pin: the pin top stands 2.2426 mm above the surface.
Limitations
- A rounded groove bottom does not affect the reading provided the pin touches only the flanks.
- Edge breaks reduce the actual width but not the theoretical sharp-edge width used here.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Inspect V-grooves, vee blocks and seal grooves
- Set a dial reading for groove depth
- Choose a gauge pin size
Who it is for
- Quality inspectors
- Toolmakers
- Metrology technicians
What you get
- Pin top above the surface (negative = below)
- Pin centre above the V apex
- Depth of the sharp V
- Contact height on the flanks
Interpreting the result
- Choose a pin whose contact points sit well inside the flanks.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 682–691. Topic reference; no source tables or recommended settings are reproduced.
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