Wexmar provides C932 and C954 bronze CNC machining for bushings, bearings, wear plates, valve components and pump parts. We turn and mill both alloys from continuous-cast bar, tube and plate at our shop in Canastota, New York, from single prototypes through repeat production lots. C932, also known as SAE 660 high-leaded tin bronze, is the standard bearing bronze for moderate loads, with good embeddability and conformability. C954 aluminum bronze carries much higher loads and resists wear, galling and seawater, at the cost of harder cutting.
Machinability of C932 and C954 bronze
Copper alloys are rated on their own scale, where free-cutting C360 brass equals 100 and runs several times faster than 1212 steel. On that scale C932 is approximately 70 and C954 is approximately 50. The lead in C932 breaks chips into short, manageable pieces and allows high surface speeds with carbide or even high-speed steel. C954 has no lead and contains roughly 10 to 11 percent aluminum plus iron, so it cuts more like a medium-hardness steel: chips are tougher, tool pressure is higher and edge wear shows up sooner.
Tolerances and surface finish
On bronze bushings and turned bearing parts we typically hold plus or minus 0.0005 in. on critical bores and outside diameters and plus or minus 0.001 to 0.002 in. elsewhere. Typical finishes are 32 Ra on bores and running surfaces and 63 Ra on general features. Centerless and surface grinding are available in-house for OD and flat work. These are typical results, not guarantees, and depend on wall thickness and part length. Final bushing sizes are verified with bore gages and on our Brown and Sharpe CMMs, as described on our inspection and quality page.
Tooling, chip control and distortion
C932 bearing bronze
Leaded tin bronze wants sharp, positive-rake tools with little or no chipbreaker; a heavily honed or negative edge tends to rub and smear the soft lead phase. It runs dry or with light soluble oil. The main risk is dimensional. Thin-wall bushings close up or go out of round when released from the chuck, so we use soft jaws, full-grip collets or expanding mandrels, and we rough and finish in separate operations to let the part relax. Cast bar can carry porosity, which we flag if it opens up on a sealing surface.
C954 aluminum bronze
C954 is abrasive and work hardens moderately at the cut. We use coated carbide with a honed edge, steady feed so the tool never dwells, and flood coolant to control heat. Chips can be stringy, so chipbreaker selection and peck cycles on drilled holes matter. Burrs are firm and need a deliberate deburr pass rather than a brush. Heat-treated C954 requires slower speeds and more frequent insert changes.
Heat treat and finish options
C932 is not heat treatable and is usually supplied as machined. C954 can be quenched and tempered to raise hardness and strength; that work is done through qualified outside processors, normally before final machining so any distortion is removed on the finish pass. Oil grooves, lube holes and spiral grooves are machined in-house on our live-tool lathes. Plating or impregnation of porous castings, when a drawing calls for it, is arranged through qualified outside processors.
Common bronze parts and the right Wexmar process
- Flanged and plain sleeve bushings with oil grooves and cross holes: CNC turning on Mazak and Doosan lathes with live tooling
- Thrust washers and wear rings: lathes, with surface grinding for flatness when needed
- Wear plates, gibs and slide ways in C954: horizontal machining centers with pallet changers
- Valve seats, stems and pump wear rings: lathes with Y-axis for off-center features
- Small bronze pins, bushings and bearing inserts up to 32 mm diameter: Swiss-type machines
- Worm gear blanks and lead nut blanks: turned on lathes and finished to drawing
Cost index versus 6061 aluminum
| Material | Approx. machinability (scale noted) | Cost index vs 6061 | Notes |
|---|---|---|---|
| C932 bearing bronze | 70 (C360 = 100) | 1.6 | Leaded, easy chip control |
| C954 aluminum bronze | 50 (C360 = 100) | 2.0 | Higher strength, abrasive |
| C360 brass | 100 (C360 = 100) | 1.2 | Free-cutting reference alloy |
| C260 cartridge brass | 30 (C360 = 100) | 1.6 | Gummy, formable |
| 6061-T6 aluminum | ~180 (1212 = 100) | 1.0 | Cost index baseline |
| 303 stainless | ~78 (1212 = 100) | 1.8 | Free-machining stainless |
These values are typical and illustrative for a comparable part; actual quotes depend on geometry, quantity, tolerances and mill pricing.
Applications and industries
Bearing bronze and aluminum bronze parts go into pumps, fluid power cylinders, gearboxes, conveyors, marine hardware, valves and heavy equipment. We supply industrial OEMs in pump and power transmission work, plus government build-to-print programs where material certs and heat-lot traceability are required. See the industries we serve. If a design can use a free-cutting alloy instead, compare C360 brass.
Getting a quote
Send your print and quantities and upload a drawing for an instant estimate, or call (315) 400-2654. A human estimator confirms every quote before it goes out, including availability of the bronze alloy and stock form you specify.