1. What is 3-Axis True Position?

True Position is a geometric dimensioning and tolerancing (GD&T) location control used to specify how much a feature's location may deviate from its "true" position. The 3-axis version accounts for deviations in X, Y, and Z directions.

2. How Does the Calculator Work?

The calculator uses the 3-axis True Position formula:

Where:

• \( dx \) — Deviation in X-axis (inches)
• \( dy \) — Deviation in Y-axis (inches)
• \( dz \) — Deviation in Z-axis (inches)

Explanation: The formula calculates the radial distance from the true position by considering deviations in all three axes, then doubles it to get the diameter of the tolerance zone.

3. Importance of True Position Calculation

Details: Accurate True Position calculation is crucial in manufacturing and engineering for ensuring parts fit together properly, maintaining quality control, and meeting design specifications.

4. Using the Calculator

Tips: Enter deviations in X, Y, and Z directions in inches. The calculator will compute the total True Position tolerance zone diameter.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between 2-axis and 3-axis True Position?
A: 2-axis True Position only considers X and Y deviations, while 3-axis adds the Z-axis component for three-dimensional positioning.

Q2: Why multiply by 2 in the formula?
A: The multiplication by 2 converts the radial position error into a diameter value, which is the standard way to report True Position tolerance.

Q3: What units should I use?
A: The calculator uses inches, but the same formula works with any consistent unit (mm, cm, etc.).

Q4: How precise should my measurements be?
A: For critical applications, measurements should be precise to at least 0.0001 inches (or 0.0025 mm).

Q5: Can this be used for cylindrical features?
A: Yes, 3-axis True Position is particularly useful for cylindrical features that need positioning control in all three dimensions.