Bronze gives a machine tool something a ball bearing cannot: damping. On a manual machine's screw support, that is worth more than efficiency. Machine Tools & Spindles duty is speed, stiffness and thermal growth of the spindle; the material is what decides whether the bearing survives it.
| Industry duty | high spindle speed with continuous preload and micron-level runout |
|---|---|
| Typical media | coolant mist, chips at the linear axes |
| Housing temperature | 20 to +80 °C at the housing |
| Material and grade | cast bronze (CuSn6 / C93200) |
| Hardness | 60–80 HB |
| Temperature ceiling | 250 °C |
| Corrosion / chemical | water and seawater; needs grease or graphite plugs |
| Relative cost | ≈1.5× of a standard 52100 bearing |
A rolling bearing is stiff and efficient, which is what a spindle needs. A slide needs damping: the cutting force has to be absorbed rather than transmitted, and a bronze-on-steel pair does that. It is also forgiving — a worn screw can be re-used with a new bush, and the bush is cheap. The limits are speed and the stick-slip that appears below about 10 mm/min.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Leadscrew support bush | CuSn6 bush | Bronze bush with a grease nipple | Conforms to a worn screw; replaceable without re-machining the saddle. |
| Tailstock quill | Bronze bush | Bronze bush, 0.02–0.04 mm clearance | Sliding fit with damping; no rolling elements to brinell under a clamp load. |
| Steady rest pad | Bronze pad | Bronze pad with an oil groove | Wear surface against a rotating shaft; bronze sacrifices itself. |
| Material | Fit here | Choose it when |
|---|---|---|
| Bronze | Best fit | Low-speed slides and screw supports where damping and repairability matter. |
| POM | Workable alternative | Light-load slides where lubrication is undesirable, but it creeps under a clamp load. |
| 100Cr6 / 52100 | Workable alternative | Where speed or positioning accuracy rules out sliding contact. |
Damping and repairability. A ball bearing transmits vibration into the structure and cannot be re-scraped; a bronze bush absorbs it and is replaced in minutes.
Clearance too large, or the bush was not bedded in. A new bush needs to run in under light load before the machine is pushed.
Only graphite-plugged grades, and only at low PV. Plain bronze will pick up.
Hardness, temperature, corrosion and equivalents for cast bronze.
Read →Typical duty, recommended types and suffixes for machine tools.
Read →Spindle & screw support — belt-driven spindles and leadscrew support bearings in lathes and machining centres.
Read →High speed spindles — high-speed machining and motorised spindles running at 15,000–40,000 rpm.
Read →Send the position, bore size, quantity and the medium it sees. We reply with the material certificate, clearance class, lubricant and price within 30 minutes on working days.