Bars

What are bars?

The bars in this range are oil-filled bronze bars, also known as oil-impregnated or sintered bronze bars. They are supplied as solid round lengths of self-lubricating bronze, ready to be cut, turned, and bored to make custom plain bushes, bearings, thrust washers, spacers, and wear parts. Bronze bar is ideal when a standard off-the-shelf bush is not available in the size you need, or when you need to make a one-off part for a repair.

Oil-filled bronze is made by pressing and sintering fine bronze powder, which creates a material full of tiny interconnected pores. These pores are then filled with lubricating oil. As a shaft turns inside a bush made from this material, heat and movement draw the oil out to form a thin lubricating film. When the shaft stops and the bush cools, most of the oil is drawn back into the pores, ready for next time. This makes oil-filled bronze self-lubricating and low-maintenance.

Bars are usually described by their outside diameter and length, in metric or imperial sizes, such as 3/4 × 2 inch or 1/2 × 6 inch.

Key features:

• Self-lubricating - oil stored in the pores lubricates the bearing surface during use
• Low maintenance - reduces or removes the need for regular greasing or oiling
• Easy to machine - can be cut, turned, bored, and drilled to make custom parts
• Smooth, quiet running - the oil film gives low friction and quiet operation
• Good wear resistance - bronze is a proven bearing material that wears evenly and protects shafts
• Corrosion resistant - bronze resists rust, making it suitable for damp environments
• Range of sizes - available in different diameters and lengths for custom parts

In simple terms, oil-filled bronze bar is self-lubricating bearing material that can be machined into custom bushes and wear parts.

Why are bars essential?

Bronze bars are essential because not every bearing or bush can be bought ready-made. Older machinery, special designs, and worn parts often need bushes in non-standard sizes, unusual lengths, or with flanges, grooves, or holes that standard parts do not have. Oil-filled bronze bar lets engineers and workshops make exactly the part they need, quickly and economically, while still getting the benefits of a self-lubricating bearing.

Their main benefits are:

• Custom parts - make bushes, washers, and wear parts to any size or shape within the bar’s dimensions
• Fast repairs - produce replacement parts in the workshop without waiting for special orders
• Keeps older machinery running - replace obsolete or hard-to-find bushes
• Self-lubricating performance - custom parts still benefit from built-in oil lubrication
• Reduced maintenance - ideal where regular lubrication is difficult or not practical
• Shaft protection - bronze is softer than steel shafts, so wear happens in the bush rather than the shaft
• Cost-effective - often cheaper than ordering specially made bushes

Oil-filled bronze bars are used across a wide range of industries and applications, including:

• Maintenance and repair workshops - making replacement bushes and wear parts
• Agricultural machinery - pivots, linkages, and shaft supports
• Electric motors and fans - small shaft bearings and sleeve bearings
• Industrial machinery - bushes, guides, and thrust washers
• Pumps and gearboxes - plain bearings and spacers
• Automotive and classic vehicles - custom bushes for older vehicles
• Model engineering and prototyping - one-off bearings and parts
• Packaging and food machinery - low-maintenance bearings and guides

The main types of bars

Bronze bars are usually grouped by their shape, material, and size.

By shape:

• Solid round bars - solid lengths of bronze that can be turned and bored to make bushes, sleeves, and washers of any internal size
• Hollow or cored bars - bars with a pre-formed bore, reducing machining time and waste when making bushes
• Plate and flat bar - flat sections used for wear strips, thrust plates, and slide pads

By material:

• Oil-filled sintered bronze - porous bronze impregnated with oil, giving self-lubricating properties. Ideal for light to medium loads and moderate speeds
• Solid cast bronze - dense bronze without oil-filled pores, used for heavier loads and shock loads, usually needing external lubrication
• Graphite-plugged bronze - bronze with solid lubricant inserts, used for slow speeds, high loads, and high temperatures

By size:

• Imperial sizes - diameters and lengths in inches, such as 1/2, 5/8, and 3/4 inch diameters
• Metric sizes - diameters and lengths in millimetres

How to choose the right bars?

Choosing the right bronze bar means making sure it is large enough to make the part you need and suits the application. Work through these points in order:

• Finished part size - choose a bar with an outside diameter slightly larger than the finished part, allowing material for turning to size
• Bore size - check that the finished bore suits the shaft, leaving enough wall thickness for strength
• Length - choose a bar long enough to make the part, allowing extra for holding in the lathe chuck and cutting off
• Metric or imperial - check whether the shaft and housing are metric or imperial, and choose a suitable bar size
• Load - oil-filled bronze suits light to medium loads. For heavy or shock loads, consider solid cast bronze
• Speed - oil-filled bronze works well at moderate speeds, where the oil film can form properly
• Temperature - check that the operating temperature suits the bronze and the oil inside it
• Lubrication access - oil-filled bronze is ideal where regular lubrication is difficult
• Shaft material - use a hardened, smooth steel shaft for the best results and longest bush life
• Quality and brand - choose bar from reputable suppliers for consistent porosity, oil content, and dimensions

FAQ: all you need to know about bars

What is oil-filled bronze?

Oil-filled bronze is a porous bronze made by pressing and sintering bronze powder, then filling the pores with lubricating oil. The oil is released during use to lubricate the bearing surface, making the bronze self-lubricating.

What can I make from oil-filled bronze bar?

It is commonly used to make plain bushes, sleeve bearings, flanged bushes, thrust washers, spacers, and wear parts.

How do I machine oil-filled bronze?

Use sharp tools, light cuts, and moderate speeds, and avoid using water-based coolants, which can contaminate the oil and close the pores. Avoid grinding or heavy polishing, which can smear and close the pores on the bearing surface.

Do I need to add oil after machining?

Machining can release some of the oil from the bronze. Many engineers soak finished parts in warm oil to top up the oil content before fitting. Use an oil suitable for the application.

How should I fit a bush made from oil-filled bronze?

Bushes are usually pressed into a housing with an interference fit. The bore will close slightly when pressed in, so allow for this when machining, or check the bore size after fitting. Avoid hammering the bush directly.

Do oil-filled bronze bushes need extra lubrication?

In most cases they are self-lubricating and need little or no extra lubrication. In demanding conditions or for long service intervals, occasional light oiling can help extend their life. Avoid thick greases, which can block the pores.

What loads and speeds are oil-filled bronze bushes suitable for?

They are best suited to light to medium loads and moderate speeds. For heavy loads, shock loads, or very slow movement, solid cast bronze or graphite-plugged bronze may be a better choice.

What shaft should I use with a bronze bush?

A hardened, smooth, and accurately sized steel shaft gives the best results. Rough or soft shafts increase wear and reduce bush life.

Can oil-filled bronze be used in wet conditions?

Bronze resists corrosion and works well in damp conditions, but water can wash out or contaminate the oil over time. For very wet environments, consider occasional relubrication or an alternative bearing material.

How do I know when a bronze bush needs replacing?

Signs include excessive play, noise, squealing, increased heat, visible wear, or a shaft that no longer turns smoothly. Worn bushes should be replaced to protect the shaft and keep the machine running smoothly.