Splined mitre joint (hidden spline) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/splined-mitre-joint/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design — geometry computed in the generator from traditional proportions
Catalog version: 2026-10-20

Overall (mm): length 80.0, width 80.0, height 20.0
- Woodworking joint drawn for 3D printing: the parts lock together by shape, so a print can be joined without glue or screws. Drawn at true size with the parts line to line (zero gap) in their assembled position — add your printer's fit allowance to the mating faces (your AI or slicer can do this).
- A thin spline across the mitre faces lines the corner up and stops it slipping.

dimension  value
stock  20 × 20 mm square
parts  part a, part b, spline
mitre  45°
spline  3 mm thick, 18 mm along the mitre, 10 mm across it, hidden inside
assembles  spline into one slot, close the mitre
holds  keeps the mitre aligned and adds strength

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Xem Studio: Joinery design (geometry computed in the generator from traditional proportions) — web — Xem Studio design — https://xemstudio.com/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 4 parts): https://xemstudio.com/files/hardware/splined-mitre-joint/index.json
API: https://xemstudio.com/api/geometry?object=splined-mitre-joint