5160 vs 1084
Two forging-shop staples that split cleanly by blade size. 1084 is the simplest steel in knifemaking and takes a harder edge; 5160 gives up hardness and edge life in exchange for toughness that lets a long blade survive real abuse. Draw the line at about eight inches and the choice mostly makes itself.
Quick Verdict
Choose 5160 for anything long, thick or destined to chop — swords, machetes, kukris, big camp knives. Choose 1084 for smaller blades, first projects and anything where a keener, harder edge matters more than surviving impact.
Toughness
5160 wins clearly. Lower carbon means less excess carbide, and the chromium and manganese give clean deep hardening — the combination bends and returns where 1084 would chip. Run at its intended 57 to 59 HRC, it is one of the toughest steels a beginner can buy.
Edge Retention
1084 wins. At 0.84% carbon it hardens to 58 to 61 HRC against 5160's 57 to 59, and in low-carbide steels hardness is what drives edge life. Neither has alloy carbides, so both resharpen very quickly — the gap is real but easy to live with.
Corrosion Resistance
A tie, and a poor one. 5160's ~0.8% chromium is a hardenability alloy, not a stainless one, and 1084 has essentially nothing. Both patina fast and rust if neglected.
Heat Treat
Both are forge-friendly, with 1084 the simpler of the two. 1084 is eutectoid: magnet heat, fast oil, temper 400 to 425°F, no soak required. 5160 wants about 1525°F with a 10 minute soak and a medium-fast oil, then 400 to 450°F to land 57 to 59 HRC. 5160's better hardenability is a real advantage on long blades, which crack less in a gentler quench.
Grinding
Both grind easily annealed and hardened. 5160 is more often bought as reclaimed leaf spring, which arrives with scale and unknown history — new bar stock behaves far better and is worth the small premium.
Best-Use Scenarios
5160: swords, machetes, kukris, camp choppers, large bowies, tomahawks. 1084: first knives, hunters, utility and camp knives under about eight inches, and the dark layer in damascus.