Definition
A screw thread form in which three separate, parallel helical threads are cut around the same shaft, allowing the nut or fitting to advance three times the distance per revolution compared to a single-thread fastener of the same pitch.
Plain English
A bolt or shaft with three threads wound around it side by side instead of just one, so it screws on or off much faster for the same amount of turning.
Context Anchor
Seen in aircraft maintenance when identifying special screws, threaded sleeves, adjustment parts, or mechanical parts that must move a set distance when turned.
Derivation
From 'triple' (three) and 'thread' (the helical ridge wrapping a screw). The name describes the construction directly: three threads instead of one.
Why Pilots Care
Quick-release fasteners on aircraft -- like fuel caps and inspection panel screws -- often use multi-thread designs so they can be opened and closed quickly during preflight or refueling without sacrificing a secure fit.
Analogy
A single-thread screw is like one spiral ramp around a pole. A triple thread is like three separate spiral ramps around the same pole, so a matching part can move along the ramps more quickly as it turns.
Intuition Check
Do not read “triple thread” as three separate screws or three layers of material. It means one threaded part with three spiral thread starts cut into it.
Example Sentence 1
The fuel cap uses a triple thread so it seats fully with just a one-third turn.
Example Sentence 2
Triple thread bolts allow quicker removal during engine inspections without sacrificing strength.