Sine Block Calculator
Calculate the gauge block height needed to set a sine block to any angle, or find the angle from a known stack height. Sine blocks are compact precision tools ideal for small-part inspection, tool grinding, and EDM setups.
Gage Block Height
5.0000 in
= 127.0000 mm
Quick reference \u2014 Gage block heights (inches)
| Angle | 5″ plate | 10″ plate |
|---|---|---|
| 5\u00b0 | 0.4358 | 0.8716 |
| 10\u00b0 | 0.8682 | 1.7365 |
| 15\u00b0 | 1.2941 | 2.5882 |
| 20\u00b0 | 1.7101 | 3.4202 |
| 25\u00b0 | 2.1131 | 4.2262 |
| 30\u00b0 | 2.5000 | 5.0000 |
| 35\u00b0 | 2.8679 | 5.7358 |
| 40\u00b0 | 3.2139 | 6.4279 |
| 45\u00b0 | 3.5355 | 7.0711 |
| 50\u00b0 | 3.8302 | 7.6604 |
| 55\u00b0 | 4.0958 | 8.1915 |
| 60\u00b0 | 4.3301 | 8.6603 |
How a sine block works
A sine block uses the same trigonometric formula as sine bars and plates: sin(\u03b8) = opposite / hypotenuse. The block length between roller centers is the hypotenuse; the gauge block stack under one roller is the opposite side.
Sine blocks are preferred when working with small or cylindrical parts that fit in V-grooves, or when space is limited on the surface plate.
When to use a sine block
Small parts inspection
Hold small cylindrical or prismatic parts in the V-groove for precise angle measurement.
Tool grinding
Set cutting tools and inserts at exact relief and clearance angles for regrinding.
EDM setups
Position electrodes or workpieces at precise angles for electrical discharge machining.
Quality control
Verify machined angles on production parts using indicator sweeps.
Compact workspaces
Sine blocks take less space than sine bars or plates on crowded surface plates.
Cylindrical parts
V-groove design securely holds round parts that would roll off a sine bar.
Frequently asked questions
What is a sine block?
A sine block (also called an angle gage block or sine vise block) is a compact precision tool similar to a sine bar, but with a solid rectangular block form factor. It typically features a V-groove or clamping mechanism on top for holding cylindrical or small workpieces at precise angles.
How is a sine block different from a sine bar?
A sine block is shorter and more compact than a sine bar, making it ideal for small parts and tight setups. It often includes built-in clamping features. The math is identical — Height = Length × sin(Angle) — but sine blocks are typically available in 2.5", 5", or 100 mm lengths.
How is a sine block different from a sine plate?
Sine plates have a wide, flat surface for large workpieces and heavy-duty operations. Sine blocks are compact and designed for small, precise work like inspection of cylindrical parts, tool grinding, and EDM setups. Plates clamp from above; blocks often hold parts in V-grooves.
What are common sine block sizes?
Common sine block lengths include 2.5 inches, 5 inches (imperial) and 100 mm, 200 mm (metric). The 5-inch size is most popular in North American machine shops.
When should I use a sine block vs a rotary table?
Use a sine block when you need static angle positioning with gauge-block precision (arc-seconds). Use a rotary table when you need continuous rotation or indexing. Sine blocks are simpler, cheaper, and more accurate for fixed-angle setups.
How do I calculate gauge block height?
Use the formula: Height = Block Length × sin(Angle). For a 5-inch sine block at 15°: Height = 5 × sin(15°) = 5 × 0.2588 = 1.2941 inches.
Can sine blocks handle steep angles?
Sine blocks work best for angles up to about 45°. Above that, accuracy decreases and the setup becomes unstable due to the compact form factor. For steep angles, use a sine plate or compound angle fixture.
What industries use sine blocks?
Sine blocks are used in precision machining, tool and die making, aerospace manufacturing, automotive quality inspection, EDM (electrical discharge machining), and metrology laboratories. Any application requiring precise angular positioning of small parts benefits from sine blocks.