Graphite Plugged Bronze Bushings
Self-lubricating cast bronze bearings with embedded graphite plugs. Maintenance-free operation up to 400°C for mold & die, steel mills, and heavy industrial applications.
What Are Graphite Plugged Bronze Bushings?
Graphite plugged bronze bushings are self-lubricating bearings made from cast bronze with holes drilled and filled with solid graphite lubricant. The distinctive appearance — a golden bronze base covered with black graphite plugs — makes these bushings instantly recognizable.
Unlike traditional cast bronze bushings that require periodic oil or grease lubrication, graphite plugged bearings are completely maintenance-free. The embedded graphite acts as a permanent solid lubricant that transfers to the shaft surface during operation, creating a self-replenishing lubricating film.
JBM graphite plugged bushings are manufactured from high-strength cast bronze alloys with precision-drilled holes filled with specially formulated graphite compounds. They excel in applications where conventional lubrication is impractical — high temperatures, clean environments, or hard-to-reach locations.
Graphite Coverage & Pattern
Optimal graphite-to-bronze ratio. Less = insufficient lubrication. More = reduced load capacity.
Geometric pattern ensures continuous lubrication film in any sliding direction.
Standard plug diameter. Custom sizes available for special applications.
Technical Data
| Base Material | Cast Bronze Alloy |
| Lubricant | Solid Graphite Plugs |
| Surface Coverage | 20-30% |
| Max Static Load | 100-120 N/mm² |
| Max Speed (Dry) | 0.5 m/s |
| PV Limit | 1.65 N/mm²·m/s |
| Temperature Range | -40°C to +400°C |
| Friction (Dry) | 0.08 - 0.18 |
| Lubrication | Maintenance-Free |
Industry Equivalents
JDB • 500# Series • Oiles 500 • MPBZ • Graphalloy
Direct replacement for all major OEM specifications
Solid Lubricant Film Transfer
Graphite plugged bushings work on a simple but effective principle: friction creates a protective lubricating film that continuously replenishes itself.
Friction Generates Heat
As the shaft rotates or oscillates, friction between the shaft and bearing surface generates localized heat at the contact points.
Graphite Expands & Transfers
Heat causes the graphite plugs to expand slightly. Graphite particles transfer (smear) onto the shaft surface, forming a thin solid lubricant film.
Protective Film Forms
The graphite film creates a separation layer between the bronze and shaft, dramatically reducing friction and preventing metal-to-metal contact.
Self-Replenishing
As the film wears, fresh graphite continuously transfers from the plugs, maintaining lubrication throughout the bearing's service life.
Why "Plugged" is Better Than "Coated"
Graphite Plugged
- Lubricant embedded through full wall thickness
- New graphite exposed as surface wears
- Lifetime lubrication — no reapplication needed
- Handles heavy loads without lubricant loss
Surface Coated
- Thin lubricant layer on surface only
- Coating wears away over time
- May need recoating/replacement
- Limited load capacity before breakthrough
Cast Bronze Alloy Grades
JBM offers graphite plugged bushings in multiple base alloys. Select the bronze grade that best matches your load, temperature, and environmental requirements.
| Property | High Tensile Brass | Aluminum Bronze |
|---|---|---|
| Alloy Code | C86300 / CuZn25Al5Mn4Fe3 | C95400 / CuAl10Ni5Fe4 |
| Appearance | Golden Yellow | Darker Gold / Bronze |
| Max Load | 100 N/mm² | 120 N/mm² |
| Temperature Range | -40°C to +300°C | -40°C to +400°C |
| Corrosion Resistance | Good | Excellent (Seawater) |
| Hardness | HB 210+ | HB 180+ |
| Best For | General high-load applications | Marine, chemical, high-temp |
| JBM Model | JBM-650 | JBM-650 (Al-Bronze option) |
Why Choose JBM Graphite Plugged Bushings
Maintenance-Free
Self-lubricating design eliminates oil/grease maintenance. No lubrication points to service throughout bearing life.
Extreme Temperature
Operates continuously up to 400°C with aluminum bronze base. Outperforms any polymer bearing in high-heat environments.
Heavy Load Capacity
Cast bronze base handles static loads up to 120 N/mm². Ideal for slow-speed, high-load applications.
Clean Operation
No oil or grease to leak or contaminate products. Perfect for food, pharmaceutical, and cleanroom environments.
Water & Chemical Resistant
Graphite lubrication works in water and many chemicals. Aluminum bronze option excels in seawater and corrosive environments.
Impact Resistant
Solid cast bronze construction absorbs shock loads. Graphite plugs won't crack or fail under impact like coatings.
Self-Repairing Film
Graphite film continuously replenishes from embedded plugs. Minor surface damage "heals" as new lubricant transfers.
Custom Shapes
Cast bronze can be machined into bushings, wear plates, guide rails, and complex custom geometries.
We typically respond to inquiries within 12 hours. Get expert recommendations for your application.
Get a QuoteMold & Die, Steel Mills, Heavy Industry
Graphite plugged bushings excel where conventional lubrication is impractical — high temperatures, clean requirements, underwater operation, or hard-to-reach locations.
Mold & Die Industry
- Injection mold guide bushings
- Die set guide pins
- Press die wear plates
- Ejector pin bushings
- Blow mold clamp guides
- Stamping die guide posts
Steel & Metallurgy
- Furnace cart bearings
- Rolling mill chock liners
- Continuous caster guides
- Ladle car pivots
- Hot strip mill guides
- Coiler mandrel bushings
Water & Marine
- Sluice gate hinges
- Dam gate bearings
- Lock gate mechanisms
- Ship rudder bearings
- Hydraulic turbine guides
- Underwater equipment
Heavy Equipment
- Crane boom pivots
- Excavator linkages
- Mining conveyor bearings
- Tunnel boring guides
- Bridge expansion bearings
- Press slide gibs
Bushing Types & Custom Shapes
Cylindrical Bushings
Standard sleeve design for shaft support. Press-fit or clearance fit installation.
ID: 20mm - 300mm+
Flanged Bushings
Integral flange provides thrust surface and axial location.
ID: 20mm - 200mm+
Wear Plates
Flat plates for sliding surfaces, guide rails, and wear pads.
Custom sizes
Thrust Washers
Ring bearings for axial thrust loads with graphite plugs on face.
OD: 30mm - 400mm+
Guide Bars
Rectangular bars for linear sliding applications.
Custom profiles
Custom Shapes
Machined to your drawing. Any shape that can be cast and drilled.
Per specification
Need Graphite Plugged Bronze Bushings?
JBM manufactures graphite plugged bearings in high-strength brass and aluminum bronze. From mold guide bushings to steel mill bearings, we deliver maintenance-free solutions for extreme environments.
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