CNC and 3D printing

The lure is split down its vertical centre plane into a mirrored pair. Every internal feature — wire groove, hanger twist pockets, ballast pockets, weight-transfer channel, chambers, bubble channels and registration pins — sits on the flat glue faces, so it can be cut or printed from one side.

Layout

Both halves on one blank, back to back, symmetric about the long centre line, grain along the length.

Pass 1 — glue face

Cut grooves and pockets (glue-face STL, or the DXF/SVG/PDF drawing for 2D toolpaths) and drill the two flip holes through.

Flip

Turn the blank end over end onto dowels in the spoilboard through the flip holes.

Pass 2 — shape

Rough and finish the half-bodies from the shape STL; tabs hold each half to the frame.

Glue-up

Cut the tabs, fit wire, hangers and ballast, glue on the registration pins.

The print pair lays both halves glue-face down so the grooves need no support. Wire and pin clearances are separate from the CNC ones and tuned per printer. PETG or ASA stand up to salt and sun better than PLA. Buoyancy uses the print material density and modelled chambers rather than slicer infill, so tank-test the first print.

Unsealed Paulownia takes on water, end grain about three times faster than side grain. Seal the nose, tail, wire exits and hanger holes first, then build up two or three epoxy coats; the coating mass is part of the buoyancy calculation.