Definition
A replacement stud used to repair a damaged threaded hole in an engine case or other component. The lower (installed) end has a larger diameter than the original stud, while the upper end retains the original thread size. The oversize lower threads cut into fresh metal in the repaired hole, while the standard upper threads still accept the original nut.
Plain English
A repair stud that is fatter at the bottom than at the top. The fat end grips into a re-tapped hole in the engine case, and the normal-sized top end still works with the regular nut.
Context Anchor
Seen in aircraft maintenance, especially when repairing a damaged threaded hole in an engine case, accessory pad, or other metal part.
Derivation
Called 'step' or 'stepped' because the stud has two distinct diameters along its length, like a step. The change from one diameter to the other forms the visible 'step' on the stud.
Why Pilots Care
Provides secure, aligned attachment in high-vibration areas, reducing risk of loosening or misalignment that could lead to component failure.
Analogy
Think of it like a double-ended screw where one end is made larger to grip a repaired hole, while the other end stays the original size so the normal nut or part still fits.
Intuition Check
Do not read “step” as a footstep or a procedure here. In this term, “stepped” means the stud changes size from one threaded end to the other.
Example Sentence 1
The mechanic installed a step stud in the crankcase after the original stud hole was found to be stripped during cylinder reinstallation.
Example Sentence 2
Each stepped stud was torqued in sequence to ensure even clamping force on the magneto flange.