Customizable Vernier Caliper: 150 mm (0.05 mm) and 100 mm (0.1 mm) Presets, Teaching Model

This is a customizable vernier caliper. Change one variable in the TrueGeometry Playground recipe and the whole model changes: RANGE resizes the beam and scale, VN switches the vernier between a 0.05 mm and a 0.1 mm reading, G moves the slider to any reading you want to show.

It is a teaching model for how a vernier scale works. Two presets are included:

- Compact: 100 mm range, 0.1 mm vernier (10 divisions). Print this one first.

- Standard: 150 mm range, 0.05 mm vernier (20 divisions). A demonstration of the principle.

Each preset is two parts that print flat, top face up: the beam with the fixed jaw (raised 1 / 5 / 10 mm ticks and cm numbers), and the slider (sleeve with 0.4 mm clearance per side, sliding jaw, vernier plate, thumb grip ridges).

FILES

The first file in the list is the full assembly of the compact preset (beam and slider together, set to a 23.4 mm reading). It is for looking at and for slicing as one plate. The component files follow: beam and slider for each preset, then the standard assembly. Recipes (.txt) and the how-to guide PDF are attached.

HOW THE VERNIER MATH WORKS

Vernier pitch = (2n - 1) / n mm. With 20 divisions the pitch is 1.95 mm, so each vernier tick is 0.05 mm behind a main tick. Read whole millimetres at the vernier zero. Find the vernier tick that lines up with a main-scale tick. Its number times the step is the fraction.

Example: reading 23.35 mm. The zero sits just past 23 mm and vernier tick 7 coincides, so 23 + 7 x 0.05 = 23.35 mm. On the compact preset at G = 23.4, tick 4 coincides: 23 + 4 x 0.1 = 23.4 mm. I checked both coincidences against the exported geometry.

CUSTOMIZE IT (TrueGeometry Playground)

Paste a recipe into the Script panel, press Run in an empty scene. The variables are at the top, one per line:

RANGE = 100 (beam range in mm, steps of 10)

VN = 10 (10 = 0.1 mm vernier, 20 = 0.05 mm)

G = 23.4 (slider position = the reading shown)

C = 0.4 (sliding clearance per side, tune it for your printer)

The full Playground commands are in the blog article and in the attached recipe files:

https://blog.truegeometry.com/0_0_0_0/blogs/post-e38e72ec.html

The recipes use variables, arithmetic in arguments and one /array line. If you change RANGE, add or remove the cm number blocks to match.

PRINT SETTINGS

0.4 mm nozzle or smaller, 0.12 to 0.16 mm layers, no supports, print flat. The standard beam is 203 x 58 mm, so it needs a bed of about 205 x 60 mm. The compact beam is 133 mm long.

HONEST NOTES

- Unprinted and untested. I checked everything in CAD and on the exported meshes, not on a printer.

- Not a calibrated or certified measuring instrument. It is a teaching model.

- The 0.05 mm preset is a demonstration only. FDM tick placement error is about 0.1 to 0.2 mm, larger than the 0.05 mm step. Print the 0.1 mm preset.

- Sliding fit is untested. The slider has 0.4 mm clearance per side in CAD. You may need a different C.

- Outside jaws only. No depth rod, no lock screw, no inside jaws.

- The numbers use the blocky pixel font the Playground falls back to for sketch text.

- Mesh: 0 zero-area triangles and 0 open (boundary) edges in every file. The models are built from overlapping shells without boolean unions, so each file has some non-manifold edges where shells touch or overlap (19 to 174 per file). Slicers normally merge these.

- Preview images are renders of the exported STL (coloured by height), not Playground screenshots.

PLEASE TEST-PRINT IT

If you print one, please post a Make and tell the community how the slider fit and the tick legibility came out. Test prints are the missing piece.

AI DISCLOSURE

Yes. AI-assisted design, recipe preparation, checking and writing.

Licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Commercial use requires TrueGeometry's consent.

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