Prop Bolt Calculator

For fixed-pitch propellers. Ground-adjustable and constant-speed setups vary. Please call us. Always double-check thread engagement and safety-wire access before flight.

Extension mode Bolts from the prop into a Saber extension. Back to the standard calculator

1. Your setup

Bolt diameter3/8″7/16″1/2″

EngineO-200 (flange .25″)O-235 (flange .19″)O-320 standard flange (.27″)O-320 heavy-duty flange (.38″)O-360 / O-540 standard flange (.38″)O-360 / O-540 heavy-duty flange (.44″)Other / not a Saber lug

O-320, O-360 and O-540 come with a standard or heavy-duty crank flange. Measure your crank flange thickness at the bolt holes and pick the closest match, or choose Other to enter it.

Engine (crank) flange thickness (in)Drive lug head height (in)

Flywheel / ring gear between engine flange and prop (+.25″)

Extension length1.251.51.7522.252.52.753468

2. What’s in the stack

Prop hub thickness (in)

Measure the prop hub at the bolt holes.

Crush plate thicknessNo crush plate.25.375.5.625.751Other (enter thickness)

Spinner bulkheadsNone1 bulkhead (.09″)2 bulkheads (.063″ each)Other (enter total thickness)

WasherRegular (.063″)Thin (.032″) for 7/16″ or 1/2″ solid 12H only

Anything else in the stack? (in)

Leave blank if nothing else.

Holes are not threaded (bolt goes through with a nut)

Double-checking prop bolts into a Saber extension? Use extension mode.