Definition
Threads produced by removing material from a piece of stock with a cutting tool such as a tap, die, or single-point lathe tool. The cutting action shears metal away to form the spiral grooves of the thread, leaving a finished surface that has been physically cut rather than shaped by deformation.
Plain English
Threads made by slicing metal away with a cutting tool to carve the screw shape into a bolt or hole.
Context Anchor
Seen in aircraft maintenance discussions about bolts, screws, studs, nuts, and the strength of threaded fasteners.
Derivation
“Thread” originally referred to a thin strand of fiber, like sewing thread. Screw threads got the name because the raised spiral on the fastener looks like a strand wrapped around it. “Cut” tells you the shape was made by removing material.
Why Pilots Care
Cut threads are generally weaker than rolled threads of the same size because the cutting process severs the metal grain rather than reshaping it. In aircraft hardware, knowing whether a fastener has cut or rolled threads helps in selecting the right bolt for the load it will carry.
Analogy
Cut threads are like carving grooves into a wooden dowel. Rolled threads are more like pressing a pattern into soft material without removing any of it.
Intuition Check
Do not read “cut threads” as damaged or sliced threads. Here, “cut” describes the manufacturing method: the threads were intentionally made by removing material.
Example Sentence 1
The mechanic checked the bolt's markings to confirm whether it had cut threads or rolled threads before installing it.
Example Sentence 2
Hardware with cut threads is often replaced with rolled-thread fasteners during overhaul to improve fatigue life.