KEVOS® MAKEOS · Quality
Sine-Bar Set-up (Stack Height, Rounding and Angle Error)
What gauge-block stack sets this sine bar to the angle, how much angle error do block rounding and tolerance add, and is it within my angle tolerance?
Set-up of a sine bar or sine plate: the height difference between the rollers for the angle (as the sine bar tool), the stack rounded to the resolution of the gauge-block set (and checked as buildable by the gauge block stack tool), the angle actually set by the rounded stack, the angle change per micrometre of height, the total angle error from rounding plus your stack tolerance, and the check against the angle tolerance, with a warning above 45° where sine bars lose sensitivity.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Sine bar length (roller centres) | mm | Distance between the roller centres of the sine bar or plate (common sizes 100, 200, 250 mm or 5, 10 in). |
| Angle wanted | ° | Angle the work must be set to. |
| Gauge-block set resolution | mm | Smallest step the gauge-block set can build (0.0005 mm for an 88-piece metric set). |
| Stack tolerance (sum of block tolerances) | µm | Combined length tolerance of the blocks in the stack (from the block grade; your value). |
| Angle tolerance (±) | arcsec | Tolerance on the angle being inspected or ground. |
Method and formulas
- Height H = L sin θ (as the sine bar tool); stack = H rounded to the set resolution.
- Angle set θ′ = sin⁻¹(stack ÷ L); rounding error = θ′ − θ.
- Sensitivity = 0.001 ÷ (L cos θ) radians per micrometre; total error = |rounding error| + stack tolerance × sensitivity.
- Example: 30° on a 200 mm bar needs a 100 mm stack; the set-up error is about 0.29772″ against ±10″.
Limitations
- Roller and bar errors and the surface plate flatness add to the error.
- Above about 45° a small height error gives a large angle error: use an angle block or a compound set-up.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Set a sine bar to inspect or grind an angle
- Find how accurately an angle can be set
- Check whether a longer sine bar is needed
Who it is for
- Inspectors
- Toolmakers
- Machinists
What you get
- Exact and rounded stack height
- Angle set and the error from rounding
- Total angle error against the tolerance
Interpreting the result
- A longer sine bar lowers the angle error per micrometre in proportion to its length.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 676–682, 705–708. 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.
Open the Sine-Bar Set-up (Stack Height, Rounding and Angle Error) calculator
