Maintenance Views: 13

Storing countersinks to prevent rust, and rust removal: Countersinks are HSS or carbide. HSS (including cobalt HSS) rusts easily; poor storage causes rust that hurts appearance and use; severe rust can chip edges, change sizes and scrap the tool. Part 1 - Rust-proof storage: 1) dry environment - a) dry, ventilated, humidity under 60%; b) no basements, poolsides; watch the plum-rain season in the south; c) desiccant (silica gel) in the tool cabinet, replaced regularly; 2) rust-preventive oil - a) thin coat of oil or grease on long-term storage tools, sealing out air and moisture; b) new tools come oiled - do not wipe it off until use; c) clean, dry and re-oil after use; 3) individual packaging - a) each tool in its own box, sleeve or rust-preventive paper, not mixed with other tools; b) keep original packaging (it protects); c) VCI vapor-phase paper or bags work even better; 4) tool cabinets/racks - a) dedicated dry cabinet, sorted; b) stable rack, no knocking; c) desiccant inside; 5) avoid corrosive substances - a) no acids, alkalis, salts; b) not near corrosive fumes (pickling, plating shops); c) sweaty hands off the edges (salt causes rust) - wear gloves or hold the shank; 6) periodic checks - a) check long-stored tools every 1-3 months; treat rust immediately; b) re-oil when dry; c) replace exhausted desiccant; 7) after use - a) wash with cutting fluid or kerosene to remove chips and oil; b) wipe or air-blow dry; c) oil before storage; d) never put fluid-covered tools straight back - cutting fluid rusts them. Part 2 - By material: 1) standard HSS - rusts most easily: oil + dry storage; 2) cobalt HSS (HSS-E) - slightly better but still rusts: same care; 3) carbide - does not rust (tungsten carbide), but the steel shank does: protect the shank; 4) coated tools - the coating protects, but it has micropores: edges and uncoated shanks can still rust in long storage; 5) stainless tools - stainless does not rust, but countersinks are not made of stainless (too soft). Part 3 - If rusted: 1) light rust (pale yellow film) - a) soak in oil or kerosene, wipe with a soft cloth or brass brush; b) no wire brushes or heavy sandpaper - they damage edges and sizes; c) re-oil after removal; d) light rust usually does not affect use if the edge is intact; 2) medium rust (red-brown spots, slight pitting) - a) soak in kerosene for hours to soften; b) brass brush or soft wood to remove; c) rust on the edge dulls it - re-sharpen; d) re-oil after; e) shallow pits can be saved by sharpening; 3) severe rust (thick layers, deep pits, edge damage) - a) basically scrapped: too much material removal changes size and angle; b) rust on the shank with a good edge: derust and reuse, but shank size may change - check runout; c) rust-damaged edges: scrap - do not run it (quality and safety); 4) derusting notes - a) no strong acids - they corrode the tool and damage edges; b) no grinding wheels or heavy sandpaper - they change size and angle; c) protect the edge during derusting; d) re-oil immediately after; e) coating may be damaged by derusting - be careful. Part 4 - Common mistakes: 1) leaving tools in the machine - cutting fluid and moisture rust them; remove, clean, oil at shift end; 2) wrapping in newspaper - ink and acidity rust: use rust-preventive paper or boxes; 3) mixing with other tools - knocks damage edges and invite rust; 4) touching with sweaty hands - salt rusts: gloves or hold the shank; 5) ignoring humid seasons - south plum-rain: desiccant, oil, periodic checks. Part 5 - Summary: rust prevention = dry, oiled, separate, checked. Standard HSS and cobalt HSS both rust easily - take care. Light rust can be removed; severe rust: scrap. Our countersinks ship oiled in protective packaging, suitable for long storage - ask us.