What is babbit?

• A. An alloy used for steel gears
• B. A hard ceramic coating
• C. A soft bearing material comprised of tin and lead
• D. A lubricant compound used in engines

Answer: (D)

Babbit is a soft bearing lining material used in engine bearings. It’s a low‑hardness tin‑based alloy (often containing lead and antimony) that’s cast onto bearing shells to form the surface the crankshaft rides on. Its purpose is to provide a sacrificial, conforming surface that can embed small debris and work with the oil film to prevent scoring and wear. That’s why the best description is a soft bearing material comprised of tin and lead. It isn’t a lubricant by itself, a hard ceramic coating, or a material used for gears.