Lubrication

Part of Roads and Transport

How to make and apply lubricants for axles, bearings, and mechanical joints using available materials.

Why This Matters

Friction is the invisible enemy of every machine. A dry wooden axle spinning in a wooden hub generates enough heat to char the wood within minutes of use. A metal axle in a dry iron bearing can seize solid — locked in place by welded-together metal surfaces — in under an hour of heavy use. Every unit of friction is energy stolen from productive work, converted instead to heat and wear.

Lubrication is what separates a machine that lasts decades from one that fails in days. In a rebuilding context, this matters immensely because spare parts are scarce. You cannot simply order a replacement axle or bearing. What you have must last. A properly lubricated wooden axle lasts years. An unlubricated one is destroyed in a week.

The good news is that effective lubricants can be made from materials available in almost any inhabited environment: animal fats, plant oils, beeswax, pine tar, and charcoal. None of these require industrial processing. All of them significantly reduce friction and extend the life of moving parts.

The Physics of Lubrication

Understanding what a lubricant actually does helps you choose the right one and apply it correctly.

When two surfaces move against each other, friction comes from microscopic high points (asperities) on both surfaces contacting each other. A lubricant works by inserting a thin film between the surfaces, keeping them from touching. The lubricant’s molecules slide against each other instead, and liquid-liquid friction is far lower than solid-solid friction.

Viscosity is the lubricant’s resistance to flow. High viscosity (thick) lubricants stay in place under pressure but require more energy to shear. Low viscosity (thin) lubricants flow easily but squeeze out under heavy loads. The ideal viscosity for a given application depends on the load, speed, and clearance between surfaces.

Temperature matters: Most animal fat lubricants soften or melt above 40-50°C. Heavy-use axles can generate enough heat to liquefy grease, causing it to run out of the bearing and leave the surface dry. Adding wax (beeswax, or hardened plant wax) raises the melting point.

Lubricants You Can Make

Tallow (Rendered Animal Fat)

The most widely available lubricant. Tallow is rendered (melted and purified) fat from cattle or sheep. It is semi-solid at room temperature and liquid when warm.

Making tallow:

1. Collect suet (the hard fat from around the kidneys and loins — it renders better than other fats)
2. Cut or grind the fat into small pieces
3. Heat slowly in an iron pot over low heat, stirring occasionally
4. The fat melts and separates from connective tissue (cracklings)
5. Strain through cloth to remove solids
6. Pour into containers and allow to cool
7. Store in sealed containers away from light and heat — good for 6-12 months

Properties: Good general-purpose lubricant. Melting point 40-50°C. Attracts dirt over time. Adequate for most slow-moving axles and wooden bearings.

Lard (Rendered Pig Fat)

Similar to tallow but with slightly better cold-weather performance. Pigs accumulate large amounts of internal fat (leaf lard) that renders very cleanly.

Process: Same as tallow. Leaf lard (from around the kidneys) produces the clearest, highest-quality lard. Back fat and belly fat work but contain more water and connective tissue.

Properties: Slightly softer than tallow at room temperature, lower melting point. Good for bearings that run in cool conditions.

Beeswax-Tallow Mixture

Adding beeswax to rendered fat raises the melting point and produces a grease that stays in place better under heat and pressure.

Making beeswax grease:

1. Melt beeswax in a pot (melting point approximately 63-65°C)
2. Add an equal weight of tallow and melt together
3. Stir to combine thoroughly
4. Pour into containers and cool
5. The result is a firmer, more heat-stable grease

Properties: Melting point 55-60°C. Stays in bearings better than plain tallow. Resists water washout. Excellent for wheel hubs that see rain and mud.

Pine Tar

Produced by the slow destructive distillation of pine wood (the same process as charcoal production, but collecting the liquid runoff instead of the charred wood). Pine tar is thick, dark brown, and strongly aromatic.

Producing pine tar:

1. Pack a clay-lined pit or enclosed iron vessel with pine heartwood or knots (high resin content)
2. Apply heat slowly from below — lower temperature produces more tar, higher temperature produces charcoal
3. Liquid tar drips down and out through a drain at the bottom into a collection vessel
4. Yield: approximately 5-15% by weight of the wood used

Properties: Excellent water resistance — the tar resists washout in wet conditions. Good adhesion to metal surfaces. Moderate lubrication. Traditionally used for axles of outdoor vehicles and for rope and wood preservation. Often mixed with tallow (equal parts) for a superior combined axle grease.

Castor Oil and Other Plant Oils

Various plant oils work as lubricants. The best plant-based lubricants are those with high viscosity and good oxidative stability.

Plant Oil	Source	Relative Quality	Notes
Castor oil	Castor bean seeds	Excellent	Highest viscosity, best heat stability
Linseed oil	Flax seeds	Good	Thickens over time (polymerizes) — becomes sticky
Olive oil	Olive fruit	Moderate	Good cold-weather performance, goes rancid
Sunflower oil	Sunflower seeds	Moderate	Low viscosity, needs thickening
Coconut oil	Coconut flesh	Good	Semi-solid in cool conditions, melts above 24°C

Using plant oils: Work best in enclosed bearings where they cannot run out. For open axle journals, thicken with beeswax or add to a tallow base. Straight plant oil runs off quickly in hot conditions.

Graphite Grease

Graphite (fine carbon powder from charcoal or naturally occurring graphite deposits) is an excellent solid lubricant. It works by the same principle as bearing metals — graphite’s crystal structure allows layers to slide over each other easily.

Making graphite grease:

1. Grind charcoal to a very fine powder (a mortar and pestle works, though finer is better)
2. Mix thoroughly into melted tallow at a ratio of roughly 1 part graphite to 5-10 parts tallow by weight
3. Stir while cooling to prevent the graphite from settling
4. The result is a dark gray to black grease

Properties: Graphite particles fill microscopic surface pits and grooves, creating a smoother sliding surface. Particularly effective for slow-moving, high-pressure joints. Excellent for threaded fasteners (screws, bolts) to prevent seizing. Good for metal-on-metal surfaces.

Application by Component

Different components require different lubrication approaches.

Wheel Hub and Axle Journal

This is the most critical lubrication point on any wheeled vehicle.

For a fixed axle (wheels rotate on the axle):

1. Pack grease thoroughly into the hub cavity around the axle
2. Apply grease to the axle end before inserting it into the hub
3. On wooden hubs, consider lining the hub hole with a metal sleeve (iron or bronze pipe section) — this makes a much better bearing surface and is easier to regrease
4. Check every 2-3 days during heavy use — lift each wheel slightly and spin it by hand. It should spin freely for at least 2-3 rotations. Resistance indicates insufficient grease.

Regreasing in the field:

• Remove the linchpin (the cotter or nail holding the wheel on the axle)
• Slide the wheel off
• Wipe old grease from the axle end with a rag
• Pack fresh grease into the hub and onto the axle end
• Reinstall the wheel

Keep a Grease Horn

Traditional carters kept a cow horn sealed at the tip and filled with axle grease hanging from the wagon. This grease horn allowed greasing without tools — press the tip to the axle journal gap and squeeze. Always carry enough grease for the journey plus a 50% reserve.

Gear Teeth

Gear contact surfaces need consistent lubrication to prevent wear and noise.

• For wooden gears: apply tallow or mixed grease to the tooth faces before starting and reapply every hour of operation
• For metal gears: graphite grease is superior — apply to teeth and work it in by hand-turning the gears before engaging the drive
• For slow, high-load gears (mill gears): pine tar mixed with tallow works well and stays in place

Sliding Surfaces

Drawer slides, tool guides, and any surface where two parts slide against each other.

• Beeswax rubbed directly onto wood surfaces reduces friction significantly without leaving residue
• For metal sliding on wood, thin plant oil or lard
• For metal on metal (tool beds, planer guides): graphite powder rubbed in, followed by a light oil film

Threaded Fasteners

Screws, bolts, and threaded connections exposed to rust or high stress.

• Graphite grease or pure graphite powder applied to threads prevents seizing
• Tallow works but can go rancid and become corrosive over time
• Pine tar is excellent for iron and steel threaded connections that must be removable after years

Storage and Shelf Life

Lubricants deteriorate. Rancid animal fat loses lubricating quality and can corrode metal surfaces.

Extending shelf life:

• Add salt to rendered tallow (1-2% by weight) — inhibits microbial growth
• Store in sealed containers away from light and air
• Add pine tar or wood smoke condensate (pyroligneous acid) as a natural preservative
• Keep containers cool — heat accelerates rancidity

Shelf life estimates at room temperature:

Lubricant	Shelf Life	Storage Tips
Plain tallow	6-12 months	Cool, dark, sealed
Lard	4-8 months	Cooler than tallow
Beeswax-tallow mix	12-24 months	More stable
Pine tar	5+ years	Very stable
Plant oils	6-18 months	Depends on oil type
Graphite grease	2-3 years	Graphite extends life

Frequency and Warning Signs

Regular schedule:

• Wheel hubs and axle journals: every 50-100 km of travel on good roads, or every 2-3 days of heavy use
• Gear teeth: before every session of operation, and during if runs longer than 4 hours
• Hand tools (plane soles, saw blades): after each use or when resistance increases

Warning signs that lubrication is needed:

• Squealing, grinding, or rhythmic knocking sounds from bearings or axles
• Heat detectable by touch on hubs, bearing blocks, or gear housings
• Visible dry metal surfaces with no grease film
• Increased effort required to move the vehicle or operate the machine
• Fine metal or wood dust accumulating around bearing areas

Acting immediately when these signs appear prevents damage. Ignoring them for even a few hours can destroy a bearing surface that took days to make.