A hot wire is a straight line that melts everything along its length. That single fact decides what screws and augers you can — and can't — cut. This page explains the limit, and points you at the generator that works within it: the helical flight.
Why a true screw isn't cuttable
A screw thread (or auger channel) is a local pocket wrapped in a helix. A straight wire can't carve a local pocket — as it sweeps it removes everything along an entire line, effectively a whole cutting plane, not a groove. And because the wire passes through the rotation axis, every pass cuts the centre, so no solid shaft can survive. Cutting two offset helicoids does define a flight — but only a shaftless one, with the waste lifted away. That's exactly what the helical flight generator makes.
Indexed vs synchronised rotation
An indexed cut rotates → stops → cuts a slice → rotates again; the spin only repositions the foam (this is how the ambigram works). A synchronised cut turns the A-axis while the wire moves, tracing a true helix — needed for the helical flight's toolpath. Our G-code dialect already carries the A axis, so the controller drives all axes together with no firmware changes.
What you can make instead
- Helical flight — the shaftless spiral ribbon of an auger or Archimedes screw, shown as a finished solid. The closest thing to a real screw a hot wire can make.
- Twisted columns — for a gentle twist, load any profile and turn it in the OBJECT bar (the 2-wire / 4-wire morph). A full multi-turn barber-pole isn't hot-wire-cuttable; the straight wire can only express one end-to-end ruled loft.
The honest barrier
Threads, worm gears, drill flutes with a core — all need volume removal (carving a local pocket), not a surface cut. That's the job of a voxel "foam-state" engine (on the roadmap) or a different machine (a lathe with a forming tool) — not a straight hot wire.
Related
See Rotation axis & indexed cuts for the indexed machinery, and ruled-surface architecture for the lofted (4-wire) family.