RC boat 4 mm (M4-threaded prop): prop hub dimensions
The fit dimensions PropShaper uses for e-foil and boat propellers on this mount, with the sources behind them. Open it in the studio to design a propeller around this hub and export an STL for printing.
Dimensions
| Shaft bore | ø3.3 mm |
| Hub body | ø12 mm × 10 mm long |
Source quality: Maker spec or retailer listing.
Fit notes
ETTI-standard 4 mm shafts carry props with an internal M4 thread, locked by a nut. Printed threads are weak: the 3.3 mm bore is the M4 tap drill; tap it, or open to ø4.1 around a brass M4 insert. Hub OD/height conventional.
Sources
Every dimension stays editable in the studio, so you can adjust the bore or add a set screw to match your own hardware. Printed props are prototypes: check the fit on the bench and spin them up behind a guard.