Two-Wheel Cart

Part of Roads and Transport

Building a practical two-wheel cart for one or two draft animals, carrying 200-500 kg.

Why This Matters

The two-wheel cart is the simplest and most practical wheeled vehicle for a rebuilding community. It requires only one axle and two wheels, making it far simpler to build and maintain than a four-wheel wagon. It is maneuverable — the single axle acts as the turning axis, allowing sharp turns that a four-wheel wagon cannot make. It can tip to dump loads, acting as a self-unloading vehicle. And a single draft animal can pull it, making it accessible to any household with one horse, ox, or donkey.

Two-wheel carts were the workhorse of agricultural communities for millennia. The Roman plaustrum, the medieval tumbrel, the farming cart of every peasant culture — all were variations on the same design: a platform, an axle, two wheels, and two shafts. This basic configuration carried grain, firewood, stone, dung, water, and a thousand other loads for thousands of years.

Building your first cart is a significant project — it will take a skilled woodworker several days to a week — but the result is a tool that will still be earning its keep years later. This article walks through the complete construction process from timber selection to the finished, loaded vehicle.

Design Overview

A basic two-wheel farm cart consists of:

1. Platform (body): A flat or slightly curved surface for carrying cargo, typically 1.0-1.5 m long and 0.8-1.2 m wide
2. Axle: A round or square beam running the full width beneath the platform, carrying the load and the wheels
3. Wheels: Two wheels, 80-120 cm diameter for a standard farm cart
4. Shafts: Two poles extending forward from the platform for attaching the draft animal
5. Side boards: Removable boards to contain loose cargo

Key design decision — axle position: The axle should be positioned so approximately 55-60% of the platform length is behind the axle. This means most of the load weight is behind the axle (supported by the wheels), while a small portion — including the shaft weight — extends ahead of the axle and rests lightly on the animal through the shafts. The goal: 15-25 kg of downward force on the animal’s back from the shafts, not more. More than this tires the animal and restricts its movement.

Materials

Timber requirements:

• Axle: One piece of straight-grained hardwood (oak, ash, elm), 120-150 cm long, 8-12 cm square section. The axle carries the full load, so use the best available timber.
• Shafts: Two pieces of straight, flexible hardwood (ash is traditional — it flexes slightly without breaking), 200-250 cm long, 6-8 cm diameter. Some flex is desirable to absorb road shocks.
• Platform frame: Four pieces of hardwood, 120 cm and 100 cm, 6-8 cm × 4-6 cm cross-section
• Platform decking: Planks, 3-5 cm thick, totaling the platform area
• Side boards: Planks, 20-30 cm wide, 2.5 cm thick
• Wheels: Two complete wheels with iron tires (see Spoked Wheels)

Hardware:

• Iron linchpins (or hardwood pins) to retain wheels on axle
• Iron bolts or treenails (wooden pins) for frame joinery
• Iron straps to reinforce axle-to-frame connections (optional but strongly recommended)

Construction

Step 1: Shaping the Axle

The axle is the most critical structural component. Its failure strands your cargo.

1. Select a straight-grained billet, free of knots at its center section
2. Dress it to 10 cm square with an axe and plane
3. Mark and round the final 20-25 cm of each end to a cylinder — this is the axle journal (the surface the wheels rotate on)
4. The journal diameter should be 6-8 cm — small enough for a hub hole of reasonable size, large enough to carry the load
5. The journal length should match the hub length (typically 20-25 cm) plus 3-4 cm for the linchpin washer and pin
6. Apply grease to the journal surfaces at this stage (easier than after assembly)
7. Score or groove the journal surface lightly — the scored surfaces hold grease better than smooth ones

Step 2: Building the Platform Frame

The platform frame connects the axle to the shafts and carries the cargo load.

Sill beams (longitudinal):

1. Cut two beams the full length of the platform (130-160 cm), 8 × 6 cm section
2. Mortise the axle through both sill beams at the correct position (55-60% from the front)
3. The axle should pass through or be lashed tightly beneath the sill beams — this connection carries the entire load, so it must be very secure

Cross beams (transverse):

1. Cut three or four cross beams spanning between the two sill beams
2. Connect with mortise and tenon joinery, reinforced with iron bolts or treenails
3. Space cross beams evenly along the platform length

Axle attachment: The most important joint in the entire cart. The axle must be rigidly attached to the sill beams and cannot rotate.

Method 1 (notch and bolt):

• Cut a notch in the underside of each sill beam to receive the axle
• Pass iron bolts through the sill beam and axle from above
• Add iron U-straps around the axle and bolted to the sill beams for insurance

Method 2 (through-beam):

• The axle passes through square holes mortised through both sill beams
• The axle is wedge-keyed on the outer faces of the beams so it cannot pull out
• This is stronger if the mortise is a tight fit

Step 3: Attaching the Shafts

Shafts attach to the front of the sill beams. They must be:

• Parallel to each other (spacing matches the animal’s width)
• At the correct height for the harness or collar of the specific animal
• Strong enough to resist the full push and pull forces of harnessing

1. Taper the rear ends of each shaft for a lap joint against the sill beams
2. Drill and bolt through the joint with iron bolts (minimum two bolts per shaft)
3. Reinforce with iron strap around the joint
4. Set the shafts to diverge slightly outward toward the rear (matching the animal’s body width) and parallel at the tips

Shaft height: The tips of the shafts should be at approximately the same height as the draft animal’s back. If shafts tip up or down significantly, it transfers excessive load to or from the animal’s back.

Step 4: Decking the Platform

Nail or treenail planks across the cross beams from front to back of the platform:

1. Leave 3-5 mm gaps between planks for drainage (a cart that collects water will rot quickly)
2. Notch around the axle ends where they protrude below the platform frame
3. Use planks of uniform thickness for a level surface

Step 5: Side Boards and Tail Board

For loose cargo (grain, sand, roots), add removable sides:

1. Cut notched vertical posts that drop into slots in the platform frame
2. Slide plank sections between the posts to form the sides
3. A tail board at the rear can be removed entirely for tipping operations (pushing the cart forward while it pivots on the axle, dumping the load behind)

Step 6: Fitting the Wheels

1. Slide each wheel onto the axle journal from outside
2. Add a large flat washer (iron or hardwood) against the wheel hub face
3. Insert the linchpin through the pre-drilled hole in the axle end
4. The linchpin can be a simple tapered iron rod, a wooden peg, or a cotter pin arrangement

Checking wheel clearance: With the wheels fitted, check that they clear the platform frame sides by at least 3-5 cm. A wheel that contacts the frame binds during turns and damages both components.

Checking balance: Lift the shaft ends and observe the cart attitude. It should sit approximately level with the shafts horizontal. If shaft ends drag down, the axle is too far forward (more of the platform weight is behind the axle than before it — correct this by shifting the axle position if possible, or by loading cargo more toward the front).

First Load Test

Before committing to heavy use, test the cart with a measured load.

1. Load to approximately 50% of intended capacity
2. Move the cart on the worst surface it will normally encounter
3. Listen for: unusual creaking from the axle connection (potential failure), wheel wobble (loose linchpins), shaft flex that feels excessive
4. Check the axle journal and hub temperature after 500 meters — warm is normal, hot means insufficient grease or too-tight fit

After the test, inspect all joints, linchpin holes, and the axle surface for wear. Correct any issues before full loading.

Operation and Maintenance

Loading: Put heaviest items directly over or just behind the axle. Light items at the rear. Check that the shaft load on the animal is comfortable — you should be able to lift one shaft tip with one hand when the cart is loaded correctly.

Greasing schedule: Regrease the axle journals every 50-100 km or whenever wheel hubs feel warm after use.

Shaft check: Inspect shafts for cracks or splits before each use. A shaft failure in harness can injure the animal. Replace cracked shafts immediately.

Wheel inspection: Tap each wheel spoke with a knuckle weekly during active use. Dull sounds indicate problems. Check that linchpins are secure before each long journey.