CNC Machining Materials

Bronze

At a glance

Processes

CNC Mill
CNC Lathe

Lead Time

3 days (rush)
5-7 days (standard)

Finish Options

Available as-machined, media blasted, or hand-polished

Tolerance

With drawing: as low as +/- 0.005 mm
No drawing: ISO 2768 medium

Price

$$$

Applications

Bearings, bushings, thrust washers

About the material

932 Bearing Bronze is a high strength alloy with good wear and corrosion resistance due to its tin, iron, and zinc content. It is most commonly used for bearings, bushings, and thrust washers. 932 Bronze is not heat treatable.

Material Properties

932 Bronze

Yield Strength (tensile)

18,000 psi

Elongation at Break

10%

Hardness

Rockwell B34

Density

0.322 lbs / cu. in.

Maximum Temp

500° F

McMaster Part Number

8234K21

Material Finish

932 Bronze has a shiny reddish-brown finish (slightly darker than Copper), which will vary slightly based on the specified surface finish. 932 Bronze can be polished or media-blasted to change its cosmetic appearance.

Design Recommendations

Min Wall Thickness

0.5 mm

Min End Mill Size

0.8 mm (0.03 in)

Min Drill Size

0.5 mm (0.02 in)

Max Part Size

1200 x 500 x 152 mm [x,y,z] (mill)
152 x 394 mm [d,h] (lathe)

Undercuts

Square profile, full radius, dovetail profiles

Radii : Depth

Depth must not exceed 12x drill bit diameter.
For end mills, depth must not exceed 10x tool diameter.

Cost Saving Tip

To reduce costs, limit the number of part setups, the number of inspection dimensions or tight tolerances, and deep pockets with small radii.

Bronze FAQs

Is Bronze easy to machine?

Bronze has extremely high machinability, with 642 bronze having the highest of all brass and bronze alloys. It’s known for high strength, ductility, thermal conduction, hardness, low friction properties and corrosion resistance. External CNC machining can be performed at relatively fast speeds, whereas slightly slower speeds are recommended for boring or drilling and very slow speeds for reaming.

What are the best grades of bronze for CNC machining?

Different grades of bronze can be used in many industries. 642 bronze is ductile, resistant to corrosion, fatigue, and galling, and has the highest machinability of all brass and bronze alloys. PB1 Phosphor bronze also has good machining qualities and is free machining, yet very tough.

Are coolants necessary for machining bronze?

When CNC machining bronze it can reach high temperatures when drilling and turning so the use of a coolant is recommended.

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