The mechanical reaper was a horse-drawn harvesting machine that cut and collected grain using a system of moving blades, wheels, and a platform to replace hand-cutting with scythes and sickles.

How the mechanical reaper worked

  • Horses pulled the reaper across a grain field, and their motion turned the large drive wheel on the side of the machine.
  • That wheel powered a crank that drove a straight knife blade back and forth in a sawing (reciprocating) motion along the cutter bar at the front or side.
  • The cutter bar had fingers or guards that held the stalks in place while the moving blade sliced through them near the ground.
  • A rotating reel above the cutter bar swept the standing grain toward the blade and then pushed the cut stalks back onto a flat platform on the side of the machine.
  • As the reaper moved forward, the cut grain accumulated on this platform in a layer until it was thick enough to handle.
  • A worker walking alongside used a rake to pull the gathered grain off the platform and drop it onto the ground in neat rows (windrows) for later bundling and threshing.

Key parts in simple terms

  • Horses and drive wheel – provided the motion and power for all the moving parts.
  • Cutter bar and knife – long bar with a back-and-forth blade that actually cut the stalks.
  • Fingers/guards – metal prongs that guided and held stalks straight so the blade could slice cleanly.
  • Reel – rotating arms that pushed grain into the blade and then onto the platform.
  • Platform – flat area where cut grain landed and piled up.
  • Raker (person with rake) – human worker who cleared the platform and laid the grain in rows.

Why it mattered

  • The mechanical reaper let one farmer with a horse team cut many more acres per day than workers using hand tools.
  • By combining cutting and orderly laying of grain into a single mechanical process, it drastically reduced labor and helped drive 19th‑century agricultural expansion.

TL;DR: The mechanical reaper used horse power to drive a back-and-forth knife along a cutter bar, with a reel feeding grain into it; the cut stalks fell onto a platform and were raked off into rows for later bundling and threshing.

Information gathered from public forums or data available on the internet and portrayed here.