Hollow Bearing Blanks SO16

Like all oil-impregnated sintered bearings, SO16 relies on capillary action within a network of interconnected pores that typically occupies on the order of 20-25% of the material volume. This porosity is filled with lubricating oil under vacuum impregnation. In service, frictional heat and the local pressure field at the shaft-to-bore contact draw a microscopic oil film out of the pores and onto the running surface; when motion stops and the bearing cools, capillary forces reabsorb the oil back into the matrix. The result is a self-replenishing hydrodynamic film that supports maintenance-free, dry-running operation with no external greasing.

Because the porosity is distributed through the full wall thickness of the blank, this mechanism survives machining. When you bore the Ø38 or Ø85 sample down to a final fit, the newly cut surface exposes fresh pores that are already charged with oil, so the finished bearing is self-lubricating from first rotation - provided the machining is done without pore-sealing (see installation guidance).

These are semi-finished blanks and are supplied to be machined to final dimensions before use. To preserve the self-lubricating function, observe the standard precautions for oil-impregnated sintered material:

• Machine with sharp tooling, light cuts and high surface speed. Use finishing cuts on the bore to shear the pores open cleanly rather than smearing and sealing them.
• Do not use dull tools, heavy feeds, or abrasive/lapping compounds on the running surface - these burnish and close the surface porosity, destroying oil release.
• Machine dry or with a compatible cutting oil; avoid water-based or aggressive coolants that can flush impregnation oil from the pores.
• Support the thin-wall region of the larger Ø85/Ø105 blank when clamping so chuck pressure does not distort the finished bore.
• Press the finished bush into a rigid housing with the correct interference fit. Bore closure on press-fit is normal for sintered bearings, so size the pre-press bore to allow for it and check the final running clearance after installation.
• Chamfer bore edges to ease shaft entry and avoid scraping the running surface during assembly. Re-impregnate or oil-soak the finished part if it has been extensively machined or degreased before it goes into service.

Choose the SO16 hollow blank when no catalogue finished bushing matches your required bore, OD and length combination, or when you need a wall thickness and feature set (flange, shoulder, groove) that only in-house machining can deliver. Compared with ordering a finished sintered bush, the blank trades a machining operation for complete dimensional freedom while keeping full through-wall self-lubrication. Within this family, work down from the closest oversize sample - the Ø38/Ø70 blank suits smaller bores needing a heavy wall, while the Ø85/Ø105 blank covers large-diameter bearings; both share the 120 mm length, so pick by finished OD and bore first, then part to length. If your requirement is a standard-size, ready-to-fit bearing with no machining, select a finished bushing SKU (BP25 sintered bronze or FP20 sintered iron) instead; reserve these blanks for custom, prototype and reverse-engineered work.