Sine bar & sine plate calculator
Enter the angle you want and the length of your sine bar. It gives the height of the gauge-block stack to put under the roller, and which blocks to wring together.
Safety: clamp the sine plate securely before machining and keep fingers clear of the hinge when lowering it. Don’t machine with gauge blocks left in the stack unless the plate is locked.
How it works, guides and notes
How it works
A sine bar is a hypotenuse of known length. Raise one roller by H and the top face sits at angle θ where sin θ = H ÷ L, so H = L × sin θ. Build the stack from the smallest decimal place upwards, using as few blocks as possible: each block adds a wringing film and a little error.
Worked example: 15° on a 100 mm bar: H = 100 × sin 15° = 25.882 mm (rounded to the nearest 0.0005 mm: 25.882). Blocks: 1.002 + 1.38 + 3.5 + 20.
Above about 45° a sine bar becomes very sensitive to stack error (a small height change makes a bigger angle change), so use a compound sine plate or measure the complement angle instead. Clean and wring blocks, and let them reach room temperature before measuring.
Spotted a mistake? Report an error.