Bronze Bush & Plain Bearing Guide: Sintered Oilite, Solid Bronze & Material Selection

A bronze bush is a cylindrical plain bearing — also called a sleeve bearing, journal bearing, or simply a bushing — that supports a rotating or sliding shaft with a bronze-on-steel sliding interface instead of rolling elements. It's the oldest bearing technology in industrial use (pre-dating rolling bearings by centuries) and remains the right choice across many applications where rolling bearings would be overkill, too expensive, too noisy, too vibration-sensitive, or too short-lived under shock loading.

Bronze bushes come in two structurally different families that share the name but work in fundamentally different ways: solid bronze bushes (machined from cast or wrought bronze, externally lubricated) and sintered bronze bushes (the Oilite family — pressed-and-heated porous bronze, oil-impregnated, self-lubricating). Choosing between them is the first decision when selecting a bronze bush for a service — and choosing wrong gives you a bushing that fails in weeks instead of decades.

This guide is the AU AEO reference for bronze bushes and plain bearings. It covers sintering from first principles (how Oilite is made and why solid bronze cannot be oil-impregnated), the five major bronze grades (SAE 660 / C932, manganese C863, aluminium C954, phosphor C544, nickel-aluminium C95800), the steel-backed PTFE composite families (DU, DX, Glacier), press-fit sizing rules, the re-oiling procedure for sintered bushings, why you must NEVER ream an Oilite bushing, and the cross-industry application reality — bronze bushes are used in automotive kingpins, excavator pin-and-bush assemblies (with the practitioner trick of 180° rotation at 2000 hours), marine rudder bearings, tractor PTOs, pump and compressor sleeve bearings, conveyor idlers, and hobby lathe headstocks.

AIMS Industrial stocks bronze bushes, bronze bar stock, and spherical bushings — three complementary supply categories that cover both off-the-shelf bushing replacement and bar stock for custom-machined bushings (which is what every agricultural and heavy-equipment maintenance shop needs when OEM parts are discontinued). The bronze bush + bronze bar combination is deliberate — the maintenance machinist who can't get a finished part needs the bar to cut their own.

What this guide is NOT: a rolling bearing reference (deep groove, tapered, needle, spherical roller — see our Rolling Bearings Guide for that family), a needle bearing reference (the rolling alternative for small-bore high-load), or a linear bearing reference (sliding motion, different geometry). Plain bearings complete the bearings cluster as the sliding-contact alternative to rolling-element bearings.

What is a bronze bush and how does it work

A bronze bush is a hollow cylinder of bronze (or bronze with a composite overlay) that sits between a rotating or sliding shaft and a fixed housing. The shaft turns or slides inside the bush; the bush itself stays fixed in the housing by interference fit (press fit) or by a retaining mechanism (Loctite, set screw, dowel pin). The sliding contact takes place at the inside diameter (ID) of the bush against the outside diameter (OD) of the shaft.

The sliding contact requires lubrication — without it, the metal-on-metal contact welds microscopically, tears off bronze particles, and destroys the bush within minutes of dry running. Lubrication is provided by one of three mechanisms:

1. External lubrication — oil cup, grease nipple, drip oiler, or pressure-fed circulating oil delivers lubricant to the bushing externally. Used with solid bronze (C932, C863, C954, C544).
2. Self-lubrication from oil-impregnated porosity — the bushing material itself contains oil in its pores; capillary action draws oil to the sliding surface as it heats. Used with sintered bronze (Oilite and equivalents).
3. Self-lubrication from solid film — a PTFE or polymer layer at the sliding surface provides low-friction contact without liquid lubricant. Used with composite bearings (DU, DX, Glacier types).

The bronze bush is the sacrificial wear part in the bearing system. The shaft should be harder than the bush — typical specification is Rc 50+ shaft against Brinell 70-80 HB bronze (≈ Rc 35-40). When wear occurs, the bronze wears, not the more expensive shaft. Replacing the bronze bush is cheap; re-machining or replacing a worn shaft is expensive. The hardness differential is deliberate engineering, not accidental.

Plain bearing vs rolling bearing — when to choose plain

Plain bearings (bronze bushes) and rolling bearings (ball, roller, needle, tapered) solve the same problem — supporting a rotating shaft — but with different trade-offs. The right choice depends on load type, speed, shock tolerance, noise constraint, lubrication availability, and cost.

The plain bearing wins where: heavy oscillating loads (excavator pin & bushing assemblies), shock loading (rock crushers, agricultural balers), high static load with intermittent rotation (door hinges, gate posts), corrosive environments (marine rudder bearings — bronze grades chosen for saltwater compatibility), noise-sensitive applications (precision lathe headstocks, audio equipment), and where simplicity and low cost matter more than continuous-lubrication discipline (Oilite self-lubricating in conveyor idlers, motor end bearings).

The rolling bearing wins where: continuous high-speed rotation (electric motors, pumps, gearboxes), defined L10 life is required for maintenance planning, complex alignment is uncertain (self-aligning ball bearings, spherical roller bearings), and lubrication can be sealed-for-life (greased ball bearings in HVAC fans, conveyors). See our Rolling Bearings Guide for the full rolling family.

Bronze bush vs bronze bushing vs sleeve bearing — terminology

The naming convention in Australia and globally is inconsistent. The same product is called different things by different trades and industries:

• Bronze bush / bronze bushing — interchangeable. "Bush" is the AU/UK convention; "bushing" is the US convention. Same product.
• Plain bearing — the engineering term covering any non-rolling-element bearing, including bronze, composite, and polymer types.
• Sleeve bearing — specifically an unflanged plain bearing (no shoulder for axial location). Often used in motor applications where axial location comes from the shaft assembly, not the bearing.
• Journal bearing — engineering term for a plain bearing supporting a rotating shaft (the rotating section of the shaft is called the "journal").
• Flanged bush — plain bearing with an integral flange (shoulder) at one end for axial location against the housing face.
• Oilite — proper noun, originally a Beemer/Owens-Illinois 1932 patent for sintered oil-impregnated bronze. Now used generically across all manufacturers.
• DU bushing / Glacier bearing — composite steel-backed PTFE-lined plain bearing. DU is a GGB Glacier trademark; "DU bushing" is often used generically for the broader category.

Throughout this guide we use "bronze bush" and "plain bearing" interchangeably to match the customer search vocabulary. The technical specifications apply equally regardless of which name appears on the datasheet.

Sintering explained — how Oilite is made

Sintering is the manufacturing process that creates the porous, oil-impregnated bronze that we call Oilite (or oil-impregnated sintered bronze). It is fundamentally different from how solid bronze parts are made — and the difference explains why only sintered bronze can be self-lubricating, and why solid bronze cannot.

The process has four stages:

1. Powder preparation. Bronze powder is produced by atomising molten bronze (typically 88-91% copper, 9-12% tin — close to a C907 composition) into fine spherical particles, typically 50-150 µm diameter. The composition is chosen for bearing performance, not for casting workability. Some grades include graphite or other solid lubricants in the powder mix.
2. Compression. The powder is loaded into a precision die at room temperature and compressed under high pressure (typically 200-500 MPa). The bronze particles compact together but do not metallurgically bond — at this stage the part is a fragile "green" compact that holds its shape only by mechanical interlocking of particles.
3. Sintering. The compressed compact is heated in a controlled-atmosphere furnace (typically nitrogen or hydrogen, oxygen-free) to a temperature below the melting point of bronze — typically 800-900°C, where bronze melts around 950°C. At this sub-melt temperature, atomic diffusion occurs at the points where bronze particles touch. Particles bond to their neighbours through diffusion bonding while retaining their individual identity. The result is a solid bronze body with an interconnected network of pores between the bonded particles — typically 20-30% void volume.
4. Oil impregnation. The sintered bushing is placed in a vacuum chamber containing the impregnation oil (typically ISO VG 60 to ISO VG 150, equivalent to SAE 30 to SAE 40 weight). The vacuum draws air out of the pore network; releasing the vacuum forces oil into the pores under atmospheric pressure differential. Heating the oil to 80-100°C accelerates the process and reduces oil viscosity for better penetration. The finished bushing contains 15-25% oil by volume, held in the pore network by capillary forces.

The key engineering property: the pore network is interconnected, so oil can move from inside the bushing toward the bearing surface as needed. When the shaft starts rotating, friction generates heat at the sliding surface. The local temperature rise expands the oil in the surface-zone pores; expanded oil is squeezed out onto the sliding interface where it lubricates the contact. As the bushing cools (shaft stops, or speed reduces), the oil retracts back into the pores by capillary action. The bushing self-lubricates as a function of operating temperature, with no external oil supply required.

Standard Oilite continues to function as long as oil remains in the pore network. Manufacturer-rated service life with no external lubrication is typically 1,000-2,000 operating hours at moderate PV loads before the oil supply is depleted. Beyond this, the bushing either needs re-oiling (procedure below) or replacement.

Sintered bronze vs solid bronze — when each is right

Solid bronze and sintered bronze look similar at a casual glance — both are cylindrical bronze bushes — but they are fundamentally different products with different applications, different lubrication requirements, and different failure modes.

The selection rule: if the application can supply external lubrication (oil cup, grease nipple, pressure circulation) and benefits from higher load capacity or higher temperature, choose solid bronze (typically C932 SAE 660). If the application is hard to reach for lubrication, low-load, low-speed, intermittent or oscillating, choose sintered Oilite — the impregnated oil supply lasts for years of intermittent service without any maintenance.

Oilite oil-impregnated bushings — capillary self-lubrication

Oilite-type sintered bronze bushings work by capillary action. The interconnected pore network within the bushing wall holds the impregnated oil; capillary forces in the small-diameter pores hold the oil in place against gravity. When friction heating at the sliding surface raises local temperature, oil in the surface-zone pores expands (thermal expansion of oil is roughly 0.1% per °C — significant in absolute terms). The expanded oil migrates to the sliding interface, lubricates the contact, and reduces friction.

As the bushing cools (shaft stops, or speed drops), capillary forces draw oil back into the pores. The system is self-regulating — more friction generates more heat, releases more oil, reduces friction. Less friction means less heat, less oil release, lower oil consumption. Over typical service the oil consumption rate is low enough that the impregnated oil supply lasts the operating life of the application.

The capillary mechanism has consequences for how Oilite must be handled:

• Grease blocks the pores. Grease is too viscous to flow through the pore network. Greasing an Oilite bushing seals the surface and stops the capillary lubrication. Use light oil, not grease, if external lubrication is added.
• Solvents wash out the oil. Cleaning Oilite with petroleum solvent (kerosene, brake cleaner, mineral spirits) flushes the impregnated oil out. The bushing will run dry until re-oiled.
• Machining smears the pores closed. Drilling, boring, reaming, or even excessive press-fit pressure can smear the surface bronze across the pore openings, sealing the surface. The bushing then runs dry until the surface wears through to fresh pores — by which time damage may be irreversible.
• High temperature thins the oil. Above ~100-120°C the impregnated oil viscosity drops too far for effective hydrodynamic film formation. Oilite is for low-to-moderate temperature service.

Re-oiling sintered bronze — the 80-100°C procedure

Equipment needed: a clean container deep enough to fully submerge the bushing; high-quality mineral oil at ISO VG 60-150 viscosity (SAE 30-40 weight); a way to heat the oil to 80-100°C (a hot-plate or oil-bath in a temperature-controlled environment); separate cool oil for the cooling step.

Procedure:

1. Clean the bushing — remove the bushing from service, wipe off external grease/grime with a clean rag. Don't use solvent — it will accelerate the oil loss.
2. Heat oil to 80-100°C — in the container with the bushing fully submerged. The temperature is critical: too cool (below 60°C) and oil viscosity stays too high for pore penetration; too hot (above 120°C) and the oil starts to degrade.
3. Hold at temperature for 10-15 minutes — sufficient time for thermal expansion of trapped air to push gas out of the pores, and for new oil to flow in by capillary action.
4. Cool in cold oil — transfer the bushing directly into a second container of cool oil. The temperature differential pulls additional oil into the pores by thermal contraction of the now-warm air and oil remaining in the pore network. This step doubles the oil pickup compared to cooling in air.
5. Drain and wipe — let surface oil drip off; wipe surface with a clean rag. The bushing is now ready for re-installation.

Forum-validated procedure (Practical Machinist consensus): "Re-oiling can be done by immersing in high quality mineral oil to ISO VG 60 or ISO VG 150 (SAE30 or SAE40) at 80°C to 100°C for 10 to 15 minutes and then cooling in cold oil." This is the manufacturer-recommended procedure across the major sintered bronze suppliers — GGB, Bunting, Oilite Corp, GLT-IBT.

The re-oiled bushing should perform as new for another typical service interval. Re-oiling can be repeated multiple times provided the bronze itself is not worn beyond service limits — the wear ID is the limiting factor, not the oil supply.

Why solid bronze cannot be oil-impregnated

This question comes up regularly in workshops and on forums — particularly from machinists who want to "improve" a solid SAE 660 bush by soaking it in oil for a few days. The answer is straightforward: solid bronze has no usable porosity. There is no pore network for oil to penetrate, no capillary system to hold the oil, no mechanism to release oil to the bearing surface under load.

Solid C932/SAE 660 has a microstructure of bronze grains with discrete lead inclusions; the grain boundaries are tightly fused and the lead does not form a connected network. When you immerse a solid bronze bush in oil, the oil wets the external surface and may penetrate a few microns into surface roughness — but the bulk of the bronze remains dry. After draining, the surface oil wipes off and the bushing is functionally identical to one that was never immersed.

The Practical Machinist forum has multiple long threads on this question; the consistent answer is: "Solid C932 / SAE 660 cannot be oil-impregnated because it has no interconnected pores. You can soak it in oil for years and it will hold a few drops on the surface, but it won't work as a self-lubricating bearing."

If you need a self-lubricating bushing, specify sintered bronze (Oilite or equivalent) — not solid bronze. If you have a solid bronze bushing already in place and need to lubricate it, fit an oil cup or grease nipple for external lubrication — don't try to make it self-lubricate through immersion.

Bronze grade selection — SAE 660, manganese, aluminium, phosphor

Five bronze grades dominate plain bearing supply across industrial applications. The selection is driven by load, temperature, corrosion environment, and shaft hardness.

The default for most industrial applications is C932 / SAE 660. It machines well, runs against typical hardened steel shafts, holds shape under typical industrial loads, and is the cheapest of the workhorse plain bearing grades. Bronze bar stock in C932 is the standard supply for any machine shop needing to cut custom bushings — AIMS stocks both finished C932 bushings and C932 bronze bar for this reason.

Step up to C863 manganese bronze when load increases beyond C932 capability — typically excavator pin & bushing assemblies, mining equipment pins, rock crusher pivots. The higher copper-zinc content gives higher strength but trades off some lubricity and machinability.

Step over to C954 aluminium bronze when the service is corrosive — water pumps, marine bearings, chemical service, fertiliser handling. Aluminium bronze forms a self-healing aluminium oxide layer that resists most aqueous corrosion environments.

Specify C544 phosphor bronze for sliding wear applications where the shaft cannot be hardened — gears, cam followers, light-duty journal bearings. The phosphor content gives a fine-grained microstructure with high wear resistance.

Step up to C95800 nickel-aluminium bronze only for severe marine service — FPSO rudder bearings, offshore platform applications, naval propeller shafts. The cost premium over C954 is justified by extreme corrosion resistance and high mechanical strength under cycling loads.

Industries that depend on bronze bushes — the cross-vertical reality

Bronze bushes are used across virtually every industrial vertical. The applications and challenges differ; the underlying principles do not. Below is the cross-industry application map customers ask about.

The common thread across every industry: lubrication failure is the dominant root cause of bronze bushing failure. Get the lubrication right and bushings last decades; get it wrong and they fail in weeks regardless of grade selection. The maintenance discipline matters more than the bronze chemistry.

The 2000-hour pin & bushing turn — Caterpillar's $-saving trick

This is the practitioner trick that's not in any general engineering textbook — and it can extend bronze bushing life by 2× on heavy-equipment pin & bushing assemblies. It comes from Caterpillar's recommended preventive maintenance schedule for excavator and loader pin-and-bushing joints.

The mechanism: in an excavator pin and bushing assembly, the pin rotates within the bushing across only a limited angular range — typically 90-180° depending on the joint location. Wear concentrates on the load-bearing arc of the bushing, not the full 360° interior. After typical service hours, the loaded arc is worn but the unloaded arc is essentially unworn.

The fix: at the 2000-hour preventive maintenance interval, press the pin out, rotate the bushing 180° in the housing (so the unworn arc is now in the load zone), and press the pin back in. The bushing now wears the previously-unloaded arc for another 2000 hours before requiring replacement. Total life extension: 2× the original wear life from a 10-minute pivot operation.

The trick works because:

• Pin & bushing wear is angular, not uniform
• Bushings are press-fit by interference, not keyed to specific orientation
• The bronze grade and dimensions don't change with rotation — only the wear surface presented

This is documented in Caterpillar maintenance manuals and is standard practice in earthmoving fleet maintenance. It applies to any pin-and-bushing assembly where rotation is angular rather than continuous — extending naturally to agricultural equipment hitch pins, mining equipment pivot pins, and any heavy oscillating joint with bronze bushings.

The 2000-hour pivot service typically requires the bushing to be in good condition (no surface galling, no deep scoring) — the pivot extends life from "wear" failure, not from "damage" failure. Heavily damaged bushings should be replaced, not pivoted.

DU and DX composite bushings — when bronze isn't enough

For applications where solid or sintered bronze cannot meet the requirements — dry-running with no lubrication, severe chemical environments, ultra-low friction, very high reliability — the standard alternative is the composite plain bearing family typified by GGB Glacier's DU and DX bushings. These are not pure bronze products but composite structures with bronze as one layer in a 3-layer sandwich.

The DU/DX construction:

1. Steel backing — typically 0.5-2 mm thick steel sheet, rolled into a cylinder. Provides mechanical strength, dimensional stability, press-fit retention, heat conduction.
2. Sintered bronze interlayer — typically 0.2-0.4 mm thick layer of porous sintered bronze bonded to the steel backing. Mechanical interlocking layer for the surface polymer.
3. Polymer surface — typically 0.02-0.05 mm thick PTFE-based composite (DU type) or acetal co-polymer (DX type). The actual sliding surface.

DU and DX bushings are not interchangeable with bronze bushes by drop-in fit — the wall thickness is different (composite is much thinner), the press-fit allowance is different, and the surface friction characteristics are different. Specifying DU in place of bronze typically requires re-machining the housing bore or shaft.

The advantage: composite bushings can run completely dry without external lubrication. The PTFE surface transfers a thin film of PTFE to the shaft on first start-up; subsequent rotation runs on PTFE-on-PTFE which has very low coefficient of friction (typically 0.04-0.15 vs 0.10-0.20 for lubricated bronze). The disadvantage: lower load capacity than solid bronze (the steel backing is thinner than a solid bushing of the same OD), higher cost, and the polymer surface has a hard temperature ceiling around 280°C for PTFE-based DU.

GGB retains trademark rights to "DU" and "DX" designations. Generic equivalents from other manufacturers are typically described as "PTFE-lined steel-backed plain bearings" or by their proprietary trade names (Permaglide, NORGLIDE, Tehol). AIMS sources DU/DX-equivalent composite bushings through our supplier network — contact us with the application specification.

Marine bronze grade selection — saltwater compatibility

Marine bronze bush selection is more critical than general industrial bush selection because saltwater accelerates corrosion across most copper alloys, and galvanic corrosion between dissimilar metals can destroy a bearing assembly in months.

Press-fit sizing rules — interference allowance

Bronze bushes are normally retained in their housing by interference (press) fit. The bushing OD is slightly larger than the housing bore; pressing the bushing in deforms both bushing and housing slightly to create a tight grip. Get the interference right and the bushing stays put; get it wrong and the bushing either spins in the housing (under-interference) or splits the housing on installation (over-interference).

The standard rule:

Interference greater than ~0.002" per inch of diameter can split the housing (especially cast iron or aluminium) or bulge the bushing during installation. For housings made of weaker materials than steel — cast iron, aluminium alloys — reduce the interference by 30-50% to avoid housing damage.

For Oilite specifically, the press-fit allowance is critical to ID dimension. Standard practice is to size the bushing OD against the housing bore for the desired interference, then accept the calculable ID reduction after press fit. This is the next section.

ID-shrink-on-press-fit prediction

A bronze bushing pressed into a housing under interference fit experiences radial compression. The compression reduces the bushing wall slightly inward and outward, but mostly inward — the housing bore is constrained by the housing, while the bushing ID is free to deform inward. Result: the bushing ID gets smaller after installation than it was before.

Hobby-Machinist forum practitioner consensus: "Oilite is slightly compressible because of its porosity but it transfers all of its press fit allowance into ID reduction." The same principle applies to solid bronze, though with less compressibility and lower transfer ratio.

The practical rules:

Forum-validated installation workflow: bore the housing 0.001-0.002" smaller than nominal bushing OD, press the bushing in, measure the resulting ID, and ream to final shaft fit only if necessary. For Oilite, the press-fit ID shrink typically lands within ±0.0005" of target, and any reaming risks smearing the porous surface.

Installation procedure — freeze, heat, press

Standard machine-shop procedure for installing bronze bushings — applicable to both Oilite and solid bronze:

1. Inspect — verify bushing OD, housing bore ID, planned interference. Verify the bushing has correct length and any chamfers for shaft entry.
2. Chill the bushing — freezer or dry ice for 1-2 hours. Cold bushing contracts ~0.0005" per inch per 100°F (40°C) of temperature drop. A bushing that was a tight press fit at room temperature slips in by hand at -20°C.
3. Heat the housing — to 100-150°C (oven or hot-plate). Hot housing expands; the bore is now larger. Combined with chilled bushing, the interference effectively reduces to near-zero during installation.
4. Press in straight — using a press, mandrel, or large vice, push the bushing in with even pressure along its centreline. Don't drift in with a hammer (risks cocking and damage to the bushing OD).
5. Allow to equalise — let bushing and housing return to room temperature before any reaming or shaft installation. Equalisation typically takes 30-60 minutes for normal-sized parts.
6. Check ID — measure the bushing ID after equalisation. Compare to target shaft fit. If acceptable, install shaft. If reaming is required, use a sharp reamer with light cuts (especially for Oilite — see warning below).

Alternative for small or shallow installations: bore the housing for a light interference (0.0005-0.001" per inch), drift the bushing in with a brass drift and progressive hammer taps. Suitable for small bushings under 1" OD where pressing equipment isn't available.

Alternative for very large bushings: split-line installation — bore the housing oversize, install a split bushing with retainer pins or set screws. Standard for large marine and industrial applications above ~6" OD where press-fit interference becomes impractical.

NEVER ream Oilite — the smearing failure

The mechanism: bronze is a soft, ductile metal. A cutting edge moving across a porous bronze surface plastically smears the surface bronze sideways — closing the pore openings the cutter passes over. Where you expected a clean cylindrical surface with open pores feeding oil, you get a sealed surface that cannot self-lubricate. The bushing runs dry from the moment it's installed.

Hobby-Machinist forum manufacturer consensus: "The bearing surface of Oilite bushings should not be drilled, bored or reamed. If the diameter does need to be adjusted, reaming is the proper method, but the reamer must be exceptionally sharp. Drilling, cutting or reaming Oilite bushings smears the porous surface and seals the lubricating sintered surface."

Practical workflow: size the housing bore so the press-fit ID shrink delivers the correct final ID without further cutting. If reaming is unavoidable, use an exceptionally sharp reamer, very light cut depth (0.0005-0.001"), and slow rotation with cutting oil — and accept significantly reduced bushing life.

Alternative if dimensional fit must be adjusted: machine the shaft, not the bushing. Reducing the shaft OD by a few thousandths is straightforward and doesn't compromise the bearing surface.

PV value and load/speed envelope

The PV value is the standard engineering parameter for plain bearing sizing. P is the projected pressure (load divided by projected area = load / (length × ID)), expressed in psi or N/mm². V is the surface velocity (RPM × shaft circumference), expressed in ft/min or m/s. The product PV measures the rate of frictional heat generation per unit bearing area.

Typical PV limits (continuous service, lubricated):

Published PV values are for lubricated continuous service. Dry-running PV is dramatically lower (typically 10-20% of lubricated PV). Oscillating service PV is also lower because heat doesn't dissipate uniformly. Apply derating factors for any service outside steady-state lubricated rotation.

If actual operating PV exceeds the rated value, the bushing overheats — lubricating film breaks down, friction rises, more heat is generated, lubricant viscosity drops, and the bushing enters thermal runaway. Failure follows quickly. Sizing the bushing so operating PV is below 50-70% of the rated limit provides margin for transient overloads.

Shaft hardness, surface finish, clearance — supporting parameters

The bushing is one half of a plain bearing system. The shaft is the other half, and shaft specification has direct effect on bushing life.

• Shaft hardness: Rc 50+ on the shaft against Brinell ~80 HB on C932 bronze. Harder shaft → softer bronze takes the wear (sacrificial wear part). Equal-hardness shaft + bushing → both wear, both need replacing.
• Surface finish (Ra): 0.4-0.8 µm Ra on the shaft journal is typical. Too rough (>1.5 µm) wears the bushing fast through abrasion; too smooth (<0.2 µm mirror finish) prevents the lubricant film forming and causes adhesive wear.
• Diametral clearance: ~0.001 × shaft diameter is the standard journal bearing clearance for hydrodynamic film formation. Tighter clearance increases film pressure but makes cold-start difficult; looser clearance reduces film pressure but increases vibration.
• Bushing length: typical L/D ratio of 1.0 to 1.5 (length ≈ shaft diameter). Shorter bushings have lower load capacity and higher edge-loading; longer bushings can bind if shaft alignment isn't perfect.
• Lubrication groove pattern: for externally lubricated bushings, a helical, X-pattern, or axial groove distributes oil from the oil port to the full bearing surface. Sintered Oilite has no grooves (the pore network distributes oil internally).

Common failure modes

The dominant failure modes across plain bearings, in descending order of frequency:

1. Lubrication failure — wrong lubricant, depleted lubricant, blocked oil supply, or no lubrication. By far the #1 root cause across all industries.
2. Abrasive wear — particles or dust in the bearing interface (mining, agricultural, dusty industrial environments). Cure: better sealing.
3. Fretting corrosion — vibration without sliding rotation. Common on bushings in oscillating service that should have been specified for oscillation. Cure: spherical plain bearings or specifically rated oscillating-duty bushings.
4. Overload — operating PV exceeds rated. Cure: bigger bushing, longer L/D, or specify higher-PV grade.
5. Galvanic corrosion — bronze in saltwater with electrically conductive insert (graphite plug, dissimilar-metal contact). Cure: PTFE-lined composite or matched-grade installation.
6. Smearing — Oilite bushing reamed or drilled, surface pores sealed. Cure: replace, install correctly the next time.
7. Mismatched hardness — soft shaft (Rc <40) running against bronze; shaft and bushing wear together. Cure: harden shaft or replace shaft material.
8. Loose press fit — bushing spins in housing. Cure: replace with correct interference allowance; or retain with Loctite 638/660 retaining compound.

AIMS supply — bronze bushes, bronze bar, spherical bushings

The bronze bush + bronze bar combination is deliberate supply strategy. Many AIMS customers — particularly heavy equipment fleet maintenance shops, agricultural machinery dealers, and marine workshops — need both: finished bushes for standard replacements, plus bar stock for the OEM-discontinued and one-off custom bushing applications that come up every week. AIMS is one of the few AU industrial suppliers that stocks both categories together at scale.

For specialty grades outside standard stock — C95800 nickel-aluminium bronze for severe marine service, DU/DX-equivalent composite bushings for dry-running applications, large-diameter bushings, custom bushing manufacture — AIMS sources through our supplier network. Contact us or call (02) 9773 0122 with the service envelope (shaft diameter, housing bore, load, speed, lubrication availability, environment) and we'll specify the right product for the duty.

Pairing bronze bushes with companion products: rolling bearings for the rolling-element alternative, bearing maintenance procedures for service planning, grease types for the external-lubrication grades (NOT for Oilite), industrial lubricants for oil specification, keyways for shafts that combine keyed location with bushing support.

Common bronze bush mistakes — diagnostic table

Frequently Asked Questions

What is a bronze bush and what is it used for?

A bronze bush is a cylindrical plain bearing — also called a sleeve bearing, journal bearing, or bushing — that supports a rotating or sliding shaft using a sliding bronze-on-steel contact instead of rolling elements. Used across automotive (kingpin bushings), heavy equipment (excavator pin & bushing), marine (rudder bearings), agricultural (tractor PTO), pumps, HVAC motors, conveyors, mining equipment, and hobby machining (lathe headstocks). The dominant application is anywhere shock loading, oscillating motion, noise sensitivity, or simple design make rolling bearings unsuitable.

What's the difference between a bronze bush and a rolling bearing?

Plain bearings (bronze bushes) use sliding contact between bronze and steel; rolling bearings use rolling elements (balls, rollers, needles) between hardened raceways. Plain bearings handle shock and oscillation better, are quieter, are cheaper, and tolerate vibration; rolling bearings handle higher continuous speeds, have calculable L10 life, and need less continuous lubrication. Choose plain for oscillating/shock service; choose rolling for continuous rotation at speed.

What is sintering and how is Oilite made?

Sintering is a manufacturing process where bronze powder is compressed in a die and heated to below the melting point (typically 800-900°C) until the powder particles bond at their contact points by atomic diffusion — without melting. The result is a solid bronze body with an interconnected network of pores (20-30% void volume) between the bonded particles. The pores are then filled with oil under vacuum and temperature, creating the self-lubricating sintered bronze bushing brand-named "Oilite". The trade name comes from the original 1932 patent.

What's the difference between sintered bronze and solid bronze?

Sintered bronze is powder-pressed-and-heated with 20-30% interconnected porosity filled with oil; it self-lubricates from the impregnated oil. Solid bronze is cast or wrought bronze, dense with no usable porosity; it requires external lubrication (oil cup, grease nipple, pressure circulation). Sintered Oilite is for low-load self-lubricating service to 100°C; solid bronze (C932 SAE 660 most common) handles higher loads and temperatures with external lubrication.

Can any bronze be oil-impregnated?

No — only sintered bronze with its interconnected porous structure can be oil-impregnated. Solid bronze (C932, C863, C954, C544) has dense microstructure with no usable pore network. You can soak solid bronze in oil indefinitely; it will hold a few drops on the surface but won't self-lubricate. If you need self-lubricating bronze, specify sintered Oilite — not solid bronze.

How do I re-oil a sintered bronze bushing?

Standard re-oiling procedure: immerse the cleaned bushing in high-quality mineral oil (ISO VG 60-150, equivalent to SAE 30-40 weight) heated to 80-100°C for 10-15 minutes, then transfer directly into cold oil. The temperature differential pulls additional oil into the pores by thermal contraction. The bushing comes out fully re-saturated and performs as new. This procedure can be repeated multiple times provided the bronze itself is not worn beyond service limits.

Should I grease or oil an Oilite bushing?

Oil only — never grease. Oilite's self-lubricating mechanism depends on oil flowing through the interconnected porosity via capillary action. Grease is too viscous to flow through the pore network — applying grease seals the bushing surface and stops the capillary self-lubrication. If external lubrication is added to Oilite, use light oil (typically the same ISO VG as the impregnation oil). For applications needing grease, specify solid bronze with an external grease nipple instead of Oilite.

What temperature can bronze bushings handle?

Oilite continuous service: -10°C to +100°C (the impregnated oil viscosity drops above 100°C, making self-lubrication ineffective). Solid bronze with external lubrication: -30°C to +250°C (depending on lubricant grade). DU PTFE-lined composite: -200°C to +280°C (cryogenic to high temperature). For very high temperature (above 300°C) specify dry-running graphite bushings or carbon-graphite — not bronze.

What is SAE 660 / C932 bronze?

SAE 660 (industry designation) and C932 (CDA UNS designation) are the same material: leaded tin bronze with nominal composition 83% copper, 7% tin, 7% lead, 3% zinc. It is the workhorse solid bronze plain bearing grade — moderate strength, excellent machinability, good wear resistance, requires external lubrication. The default choice for general industrial plain bearings, kingpin bushings, hydraulic cylinder rod ends, and most non-corrosive plain bearing applications.

What's the difference between SAE 660 and phosphor bronze?

SAE 660 (C932) is leaded tin bronze — 83% Cu, 7% Sn, 7% Pb, 3% Zn — with lead inclusions that improve machinability and provide some embedded lubrication. Phosphor bronze (C544) is 89% Cu, 11% Sn, 0.2% P — no lead, with phosphorus providing fine-grained microstructure and high wear resistance. SAE 660 is the general workhorse; phosphor bronze is specified where wear resistance is critical or lead content must be eliminated (food, pharmaceutical applications).

What's the difference between aluminium bronze and standard bronze?

Aluminium bronze (C954, C95400, C95800) replaces tin with aluminium (typically 9-11%) in the copper alloy. The aluminium forms a self-healing oxide layer on the surface that resists corrosion in saltwater, freshwater, and chemical environments. Aluminium bronze is significantly stronger than standard bronzes but harder to machine. Used for marine bearings (rudder, propeller shaft), pump shafts in chemical service, and any application where corrosion resistance is critical.

How much press fit do I need on a bronze bushing?

Standard rule: 0.001" interference per inch of bushing OD for diameters 1-2 inches; reduce to 0.0005-0.00125" for smaller bushings; increase to 0.0015-0.002" for larger bushings up to 4 inches. Above 4 inches, 0.002" per inch is typically the maximum to avoid housing splitting. For weaker housing materials (cast iron, aluminium), reduce all values by 30-50%. Confirm against bushing manufacturer specification for critical applications.

How much does the ID shrink when I press in a bronze bushing?

For Oilite (porous sintered), the ID shrinks by approximately the full amount of the OD interference — a 0.002" interference produces ~0.002" ID reduction. For solid bronze, the shrink is typically 50-70% of the interference. Practical workflow: bore the housing for desired interference, press bushing in, measure resulting ID, and ream only if needed to final shaft fit. Sizing the housing bore correctly often delivers final ID without any post-installation machining.

Can you ream an Oilite bushing?

Generally no. Reaming smears the porous bronze surface across the pore openings, sealing the lubricating sintered surface. The bushing then runs effectively dry until the smeared surface wears through to fresh pores — by which time the bushing may be damaged beyond use. If dimensional adjustment is unavoidable, use an exceptionally sharp reamer with very light cuts (0.0005-0.001") and accept reduced bushing life. Better practice: size the housing so the press-fit ID shrink delivers the correct final ID without further machining.

What is PV value for a plain bearing?

PV is the projected pressure times sliding velocity — the standard engineering parameter for plain bearing sizing. P is load divided by projected area (load / length × ID), in psi or N/mm². V is the surface velocity (RPM × shaft circumference), in ft/min or m/s. The product PV indicates the rate of frictional heat generation per unit area. Typical PV limits: Oilite ~50,000 psi·ft/min; C932 ~75,000-100,000; C863 ~125,000-150,000. Operate below 50-70% of rated PV for margin against transient overload.

Need to pick the right Loctite product? Our Loctite Application Guide maps every grade to its job.