Post Assembly Calculator

Calculate required post length for a target beam height, or estimate thermal drift for different post materials.

Optical posts must be sized so the beam passes through the center of each optic at the correct height above the table, and the exposed post length above the holder must not exceed the bore depth. This tool solves two related problems. Beam height mode computes the required post length given a target beam height, base type (BA2 rectangular, round, or no base), post holder bore depth, and the height from the post top to the mount's optical center. The result includes the exposed extension above the holder, with a warning if it exceeds 150 mm. Thermal drift mode compares how much a post's top-end height shifts with temperature across aluminum, stainless steel, and Invar 36, reporting height change in micrometers and the resulting angular deviation in microradians at a downstream optic distance.

Parameters
Post Length
Required post length
Target height \u2212 base height \u2212 mount center height
51.60mm
Post extension above holder
Post length \u2212 bore depth
0.8000mm
Base height used
11.90mm
Abridged Optics — Post Assembly Calculator v1.0Beam height calculations assume standard post-in-holder geometry. Thermal drift assumes uniform temperature change along the post.

All information, equations, and calculations have been compiled and verified to the best of our ability. For mission-critical applications, we recommend independent verification of all values. If you find an error, please let us know.