Sintered Bronze Sleeve Bushings | SAE 841

SAE 841 is oil-impregnated sintered bronze. It's self-lubricating with no external lubrication required. C93200 / SAE 660 is cast bronze that requires external lubrication through oil grooves or grease fittings.

Performance differs significantly. SAE 841 handles higher speeds (1,200 SFM max vs. 750 SFM) but lower loads (2,000 PSI max vs. 3,000 PSI). SAE 660 has a higher PV limit (75,000 vs. 50,000) for heavy-load applications where you can maintain lubrication.

Choose SAE 841 when lubrication access is limited or maintenance needs to be minimal. Choose SAE 660 for higher loads where external lubrication is practical.

Use sintered bronze (SAE 841) when:

• Lubrication points are dispersed or hard to reach
• You need maintenance-free operation
• Applications run at moderate loads with higher shaft speeds
• External contamination makes regular greasing impractical

Use cast bronze (C93200 / SAE 660 or similar) when:

• Loads exceed 2,000 PSI
• You have access for regular lubrication
• Operating temperature exceeds sintered bronze limits
• The application requires a higher PV rating

Steels with approximately 0.4% carbon content or higher. The 1137-1141 series works well. Drill rod and hardened/ground steels are also compatible. Hard chrome plating is recommended when corrosion resistance is needed.

Avoid soft plating. Zinc or cadmium plating will ball up during operation and clog the bushing's pores, destroying the self-lubricating properties. If stainless steel is required, use the 400 series (416 heat-treated to maximum hardness is best). Avoid 300 series.

Shaft finish should be 8-16 RMS for best performance. 32 RMS may work for less demanding applications.

Maximum PV is 50,000 psi-fpm for continuous rotation. Individual limits: maximum load (P) is 2,000 PSI, maximum speed (V) is 1,200 SFM.

Calculate PV using: P = Load ÷ (ID × Length) and V = RPM × Shaft Diameter × 0.262. Both P and V must stay within their individual maximums, and their product cannot exceed 50,000.

Operating at or near these limits reduces bearing life. Add a safety margin to your length calculation. The catalog recommends approximately 20% additional length beyond the calculated minimum.

For most applications, recommended press fit ranges from 0.001" to 0.003" for smaller ODs (under 1"), increasing to 0.002" to 0.005" for ODs up to 3". The catalog includes detailed charts by OD size.

Key consideration: the bushing ID closes in approximately 80% of the press fit amount. A 0.003" press fit typically reduces the ID by about 0.0024". Factor this into your shaft clearance calculations.

Less than normal press fit can work if the bearing is long relative to wall thickness and load is moderate and unidirectional.

Standard clearance ranges from 0.001" to 0.003" for shafts under 1" diameter, scaling up to 0.003" to 0.006" for larger shafts (3-4" range). The catalog charts show recommended ranges by shaft diameter.

Greater clearance is needed for exceptionally high speeds or higher-than-normal loading. Remember to account for ID close-in from press fit. The running clearance is the assembled ID minus shaft diameter, not the nominal bushing ID.

Standard tolerances based on ASTM specifications:

ID and OD:

• Up to 1-1/2": +.000 / -.001
• 1-1/2" to 2-1/2": +.000 / -.0015
• 2-1/2" to 3": +.000 / -.002
• 3" to 4": +.000 / -.003

Length:

• Up to 1-1/2": ±.005
• 1-1/2" to 3": ±.0075
• 3" to 5": ±.010

Concentricity: .003 TIR for sizes up to 1-1/2", increasing to .006 for 4-5" range.

Service life depends heavily on operating conditions. Properly sized bushings running within PV limits typically deliver 5,000 to 15,000+ hours. Exceeding load, speed, or PV limits accelerates wear and can cause premature failure.

Factors that extend life: adequate shaft clearance, proper press fit, appropriate shaft finish (8-16 RMS), and staying within 70-80% of maximum PV. Factors that shorten life: contamination, misalignment, inadequate clearance, soft or rough shafts, and operating near or beyond rated limits.

No. That's the point. SAE 841 bushings are impregnated with SAE 30 oil during manufacturing. The porous sintered structure releases oil during operation and reabsorbs it at rest. No external lubrication system, grease fittings, or maintenance greasing required.

One exception: at very low speeds (under approximately 200 SFM), the hydrodynamic action that releases oil is reduced. In slow-speed or oscillating applications, initial lubrication during assembly can help.

Do not use petroleum solvents for cleaning. They can wash out the impregnated oil.

The ID shrinks. Expect approximately 80% of your press fit amount. If you press with 0.003" interference, the ID will close in by about 0.0024".

This matters for shaft clearance. Calculate your final running clearance as: (Original Bushing ID − ID Close-In) − Shaft Diameter. The catalog provides charts correlating OD size, wall thickness, and press fit to help you predict close-in accurately.

If tighter shaft clearance results than intended, light reaming can restore clearance. Be conservative. Removing too much material affects the oil reservoir in the bushing walls.

Usually not necessary if you've selected the right bushing size accounting for press-fit close-in. Most standard sizes are designed to provide proper running clearance after typical press fits.

If reaming is required, remove only enough material to achieve proper clearance. Excessive reaming reduces wall thickness and oil reservoir capacity. Use sharp tools and avoid petroleum-based cutting fluids that could contaminate the oil impregnation.