Skip to content
Start a project
← Work
// 26
RefIE-026
ClientKlient prywatny
Year2026
Scale1:1
[Reverse Engineering][Automotive][CAD][3D Print]

Reverse-engineered door armrest for a 1964 Pontiac Grand Prix

A door armrest from a 1964 Pontiac Grand Prix, no longer available as a spare part, rebuilt from a single worn die casting. Measurements, a 3D model in Shapr3D with ribs and bosses for the original screws, a full set of technical drawings and geometry ready for FDM printing or MJF / SLS production.

Underside of the model: 2 mm walls, ribs every 24 mm, bosses and grooved pads in the feet.IE-026 · FIG.01 · Underside of the model: 2 mm walls, ribs every 24 mm, bosses and grooved pads in the feet.

Problem

The original armrest is a die casting nobody makes any more, and used ones are rare and expensive. A single worn piece survived. The new part has to fit the same spot: two angled threaded holes through the mounting wall at 20 degrees, two screw bosses from the face side and a notch for the door panel. The geometry had to be reproduced 1:1 from a casting that never had any documentation.

Outcome

The complete geometry of a replacement rebuilt from a single worn casting, without any manufacturer files: 272 x 74 x 45 mm, mounting points and thread angle 1:1 with the original. Plus a technical drawing (3 A3 sheets) and visualisations that the client receives together with the part.

  1. 01Measuring the worn casting: outline, face slope, position and angle of the threaded holes, boss spacing, the rib layout underneath.
  2. 023D model in Shapr3D: the outer body with the sloped face, 2 mm walls, ribs every 24 mm, screw bosses with head pockets, grooved pads in the feet.
  3. 03Geometry checks with scripts on the STEP solid (build123d): hole detection, wall and section checks before anything went to the printer.
  4. 04Documentation: three A3 sheets generated straight from the model (views, sections through the bosses and the angled thread, groove detail) in Instant Engineering branding.
  5. 05Preparation for FDM printing (PETG) plus a STEP file for possible MJF / SLS production with a partner.

Specifications

IE-026
Vehicle
1964 Pontiac Grand Prix
Part
Door armrest
Method
Reverse engineering from a casting
CAD
Shapr3D + build123d (checks)
Size
272 x 74 x 45 mm
Documentation
3 A3 sheets from the model
The worn original casting held up to the door panel, the starting point of the whole job.
FIG.02The worn original casting held up to the door panel, the starting point of the whole job.
Sheet 1 of the technical drawing: main views 1:1, hole positions and the beam notch.
FIG.03Sheet 1 of the technical drawing: main views 1:1, hole positions and the beam notch.
The original from below on a 1 cm mat: ribs, bosses and grooved pads to reproduce.
FIG.04The original from below on a 1 cm mat: ribs, bosses and grooved pads to reproduce.
Sheet 3: 2:1 sections through the boss and the 20 degree angled thread, 5:1 groove detail.
FIG.05Sheet 3: 2:1 sections through the boss and the 20 degree angled thread, 5:1 groove detail.
Face of the original: sloped surface, screw holes and head pockets.
FIG.06Face of the original: sloped surface, screw holes and head pockets.
Sheet 2: underside view with the rib layout, longitudinal section and visualisations.
FIG.07Sheet 2: underside view with the rib layout, longitudinal section and visualisations.
Next project · IE-021Ceiling lamps for Dom Sztuki Żar →