Parts of a Disc Harrow – Labeled Diagram With Names

All 13 parts on the diagram

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The whole harrow 5

Frame It carries the four gangs. Each gang hangs from it by its bearing standards.
Hitch It joins the harrow to the tractor. On this kind it is a clevis on the end of the tongue.
Front gangs They throw the soil outward, away from the middle of the harrow.
Rear gangs They throw the soil back inward, which leaves the ground level again.
Wheels The harrow is raised on them to travel. At work they also set how deep the discs cut.

One gang, close up 8

Disc blades Angled so they slice the soil, lift it and move it sideways. They are hollow on one side and set at an angle to the way the harrow travels.
Gang bolt (arbor bolt) It holds all the discs of one gang tightly together. It is square, so the discs all turn as one.
Spacer spools They hold the discs an equal distance apart. They fit over the gang bolt.
Gang bearings A gang has two or three. The gang turns in them, and each one is bolted to a standard.
Bearing standards Each joins the frame to the gang. It reaches from the frame down to a bearing on the gang bolt. Some makers call it a bearing arm.
Scrapers Scrape off the soil that sticks to the discs. One sits close to the hollow side of each disc.
Notched blade Its cut-out edge chops up stalks left from the last crop. Also called a cut-out or cutaway blade.
Plain blade Has a smooth edge all the way round. Also called a solid blade. Both kinds have a square hole for the gang bolt.

How this list was compiled: Part names checked on 2026-09-30, a name kept only when two independent sources use it. (1) H. P. Smith, Farm Machinery and Equipment (1948), sections 199 to 223, full text at https://archive.org/details/in.ernet.dli.2015.425374 (disks, disk gangs on a gang bolt or arbor bolt, spools, the frame and the standard down to the bearing, bearings, scrapers, front and rear gangs of a tandem harrow, the front gangs throwing the soil outward). (2) A tractor maker's operator's manual and parts list for a mounted disk harrow, full text at https://archive.org/details/cub-28-a-disc-harrow-12-4-51 (gangs and gang frames, arbor bolt, spacing spool, bearing and bearing standard, scrapers, hitch clevis, notched or plain disk blades, solid or cut-out). (3) A tillage maker's owner's manual for a tandem disc harrow, full text at https://archive.org/details/krause-4900-series-flex-wing-tandem-disc-harrow-owners-manual-c (main frame, tongue and hitch, front and rear gangs, disc blades, notched and cut-out blades, spacer spools, disc gang bearings and bearing arms, scrapers, wheels that regulate working depth). (4) A third maker's mounted offset disc harrow manual, full text at https://archive.org/details/manualzilla-id-6021744 (frame, hitch, front and rear gang, discs, scrapers). (5) Wikipedia, Disc harrow (concave discs set at an angle, notched disc blades that chop stover, the four sections forming an X from above, raised hydraulically by wheels). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's harrow, nothing traced. Licence: own work

How it works

The parts of a disc harrow are few, and most repeat along each row. A row of discs is called a gang; this tandem harrow has four, set in a flattened X.

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The whole harrow, then one gang

From above, find the hitch at the front, the frame and the wheels, then the two front gangs and the two rear gangs. The second drawing is one gang from behind. Every disc blade sits on the gang bolt with a spacer spool between it and the next. The gang turns in its bearings, each hung from the frame by a bearing standard, and a scraper cleans each blade.

The front gangs throw the soil outward and the rear gangs throw it back in.
Many farmers call the whole implement a disc, or a disk; both spellings are in use.

Questions and answers

What are the parts of a disc harrow called?

A frame and a hitch, then the gangs. Each gang is a row of disc blades on one gang bolt, with spacer spools between the blades, bearings the gang turns in, bearing standards up to the frame, and a scraper for each blade.

What is a gang on a disc harrow?

One row of discs fixed on a single gang bolt, so that they all turn together. An offset disc harrow has two gangs and a tandem disc harrow has four.

What is the difference between notched and plain disc blades?

A notched blade has cut-outs round its rim; a plain blade has a smooth edge. Notched blades chop up stalks left from the previous crop, such as cornstalks.

What holds the discs on a disc harrow apart?

Spacer spools. One fits over the gang bolt between each pair of discs and holds them an equal distance apart. The nut on the end of the gang bolt clamps discs and spools tightly together.