What is a three-point hitch?
A three-point hitch (also called a three-point linkage for those across the pond) is found on most tractors and used for attaching tractor-drawn farming implements for planting, haying, tilling and plowing, spreading fertilizer, brush hogging, mowing, etc. The three-point hitch also gives the tractor much better use of power, weight, and fuel because it transfers the weight of the attached implement to the rear driving wheels of the tractor, giving it much more traction. What you can accomplish with a tractor, a three-point hitch, and an implement – is immeasurable. The invention of the three-point hitch significantly contributed to modern agriculture; however, it's probably not appreciated as much as it should be. Before the creation of the three-point hitch, farmers commonly used drawbars to attach their implements - essentially like a trailer hitch on a truck having a single mounting point to pull behind trailers.
Start here: Farming with Old Tractors (practical guide)
We have Harry Ferguson to thank for the three-point hitch when he patented the mechanism back in 1926. After much trial and error, the form we mostly know today was born and started to take hold. In 1939, the "Ferguson System," as it was called, finally entered the American mass market on the Ford-Ferguson 9N.
You can tell if a tractor has a three-point hitch by checking out the rear of the tractor and looking for three arms in a triangle or letter A shape. Although it's referred to as a three-point hitch, several parts make up the system. Three moveable arms make up the system: The top link arm is at the top of the triangle, but it is usually not powered by the hydraulic system on the tractor. The two bottom arms are controlled by the tractor's hydraulic system, assist with lifting and lowering, and are located at the bottom of the triangle.
Detaching and attaching three-point hitch-compatible implements can be dangerous. It’s essential to ensure the implement is mounted correctly to the hitch for safety and the system’s efficiency. It’s also important to use the correct pin sizes and hardware for your tractor’s hitch category. In general, your implement category should match your tractor category.
Three-point hitch categories (0–4)
Category size is determined by pin diameters and lower arm spacing. Use this table as a quick reference when matching a tractor to an implement.
| Category | Typical tractor HP | Top link pin | Lower lift arm pins | Lower arm spacing |
|---|---|---|---|---|
| Category 0 | Up to 20 HP | 5/8" | 5/8" | 20" |
| Category 1 | 20–45 HP | 3/4" | 7/8" | 28" |
| Category 2 | 40–100 HP | 1" | 1-1/8" | 34" |
| Category 3 | 80–225 HP | 1-1/4" | 1-7/16" | 40" |
| Category 4 | 180+ HP | 1-3/4" | 2" | 48" |
Finally, when using or looking to buy older tractors, make sure the hitch components are correctly adjusted and not seized up with rust. A penetrating oil (PB Blaster or equivalent) plus gentle movement usually helps free stuck joints. Also ensure your tractor has enough lift capacity for the implement you’re trying to mount—some older tractors have less lift capability than newer tractors.
Start here: Farming with Old Tractors (practical guide)
The three-point hitch is arguably one of the greatest innovations in tractor history. Use it safely, and happy farming!
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