It applies the gauge marks a tensile specimen needs before it is pulled, so elongation after fracture can be measured from evenly spaced reference points instead of marks scratched on by hand.

The machine is built for labs working with metal bar, rebar and wire rod, where elongation is a reported property and preparation has to hold up across operators and shifts. A pneumatic needle rides a servo-driven lead screw, so every bar leaves the bench marked identically.

It sits between specimen preparation and the tensile test itself.