Short answer: Choose 8670 for a tough, nickel-bearing steel that holds a slightly finer edge. Choose 5160 for big blades, swords and springy tools that must flex and shrug off abuse.
You are comparing 8670 vs 5160 because both steels are tough, affordable and forgiving. That is rare in the knife world. Most steels trade one strength for another.
This guide compares the two on composition, toughness, edge life and heat treatment. We also flag what the public data cannot tell you.
Who Is This 8670 vs 5160 Comparison For?
This article suits makers, hobby forgers and buyers who read spec sheets. Every figure below comes from a named source, and we mark where numbers vary.
- Bladesmiths picking bar stock for a first or fiftieth knife
- Buyers comparing fixed blades labelled 8670 or 5160
- Tool makers who want impact resistance, not a razor edge
What Are 8670 and 5160 Steel?
8670 steel in plain English
8670 belongs to the 86xx family of low-alloy steels. According to the Knife Steel FAQ at zknives.com, the family appeared during WWII to conserve nickel and other alloying elements. It is described there as a tough steel with good wear resistance, used in circular saws and bandsaws.
5160 steel in plain English
5160 is a chromium spring steel. The same steel database calls it a simple spring steel with chromium added for hardenability. It is popular with forgers, especially for larger blades.
8670 vs 5160 Composition at a Glance
Composition drives everything else. Notice the carbon gap, and notice that only 8670 carries meaningful nickel.
| Element | 8670 | 5160 |
|---|---|---|
| Carbon | 0.70–0.75% | 0.60% |
| Manganese | 0.5% | 0.7% |
| Chromium | 0.4% | 0.90% |
| Nickel | 0.85% | Not listed |
| Silicon | 0.25% | 0.30% |
Sources: 8670 figures come from a Tactical Knives column quoted on Blade Forums. 5160 figures come from Iron Flower's construction notes. Mill specs vary slightly, so check your supplier's certificate.
Carbon content, visualised
How Do 8670 and 5160 Compare Head to Head?
| Factor | 8670 | 5160 |
|---|---|---|
| Toughness | Very high, helped by nickel | Outstanding, especially at lower hardness |
| Typical knife hardness | About 58–59 HRC in the Tactical Knives column | Low 50s for swords, near 60 for knives |
| Edge retention | Good, with more carbon on paper | Good, but less carbon |
| Spring behaviour | Not its claim to fame | Leaf-spring steel by reputation |
| Stainless? | No | No |
| Best fit | Camp knives, bushcraft, hard-use tools | Swords, machetes, large choppers |
Which Steel Is Tougher?
Both are tough, so the gap is small. Machinemfg's 8670 versus 80CrV2 comparison credits nickel for 8670's toughness.
One caution applies. A Blade Forums thread notes that not all 8670 is the same. Heat treatment and the supplier change results.
5160 earns its toughness reputation another way. The zknives entry says it performs well across a wide hardness range, with great toughness in the low 50s HRC.
Which Steel Holds an Edge Longer?
On paper, 8670 has the edge. It carries more carbon, and carbon sets the hardness ceiling.
Real life is messier, because geometry and heat treatment matter just as much. Treat the difference as small, not dramatic.
- 8670: Takes a fine edge and sharpens easily, according to Machinemfg's 8670 versus 1095 write-up.
- 5160: Reaches near-60 HRC for knives that need more edge holding, per zknives.
- Both: Neither matches high-vanadium or stainless steels for wear resistance.
How Do You Heat Treat 8670 vs 5160?
Heat treatment decides whether your steel performs or just looks the part. Always follow your supplier's data sheet first.
5160 basics
- Critical temperature sits around 1525°F, per Iron Flower.
- It can reach about 63 HRC as quenched, so tempering is essential.
- Austempering at about 600°F is listed as an option.
8670 basics
- Machinemfg suggests tempering between 300°F and 450°F.
- Higher tempering temperatures add toughness and cost hardness.
- One steel supplier calls its 8670 stable in the quench, with minimal warping.
Treat supplier claims as marketing until you test your own blades. Break a few samples before you trust a recipe.
Which Steel Suits Your Project?
- Machete, sword or large chopper: Pick 5160. It is the classic choice for long, flexing blades.
- Camp or bushcraft knife: Either works. 8670 may give a slightly finer edge.
- Kitchen or EDC knife: Pick neither first. Both rust, and thin edges favour other steels.
- Hard-use tool, such as a chisel or pry tool: Pick the one you can heat treat well.
Care matters here. Redlabel Abrasives notes that 5160 lacks corrosion resistance and needs regular cleaning. Oil your blade and keep it dry.
Common Mistakes When Choosing Between 8670 and 5160
- Using old leaf springs: You cannot know the composition, so you cannot optimise the heat treatment. Forum experts prefer new steel of known grade.
- Chasing hardness: Higher HRC is not always better. Toughness drops as hardness rises.
- Assuming any "8670" is equal: Quality varies between mills and suppliers.
- Skipping tests: A hammer test teaches more than any forum thread.
What Should You Read Next?
For deeper metallurgy, visit Knife Steel Nerds. It publishes toughness and heat-treat testing.
Planning a workshop around your new steel? Our guide to smart storage for limited space helps you fit a forge corner into a small garage. Curious how spring steel works in vehicles? Read about suspension setup on lifted trucks. Like comparison guides? Try Kerlix vs Kling, which settles a very different rivalry.
Keep a first-aid kit near your grinder. Steel comparisons are fun until someone skips the gloves.
8670 vs 5160: Frequently Asked Questions
Is 8670 better than 5160?
Neither wins everywhere. 8670 suits knives that need a finer edge. 5160 suits large blades and spring-like tools.
Is 5160 steel stainless?
No. Its chromium level is too low for stainless behaviour. Clean and oil the blade after use.
Can beginners heat treat 8670 or 5160?
Yes, both are considered forgiving. Still, use a thermometer or controlled oven, and test sample pieces first.
Why does nickel matter in 8670?
Nickel raises toughness and impact resistance, according to Machinemfg. It does not add wear resistance.
Which steel is cheaper?
Prices change by supplier and region. Compare current quotes for the bar size you need.
Final Verdict
Pick 5160 for swords, machetes and long blades. Pick 8670 for hard-use knives where a finer edge matters. If you can heat treat either well, you will not regret the choice.
Short answer: Choose 8670 for a tough, nickel-bearing steel that holds a slightly finer edge. Choose 5160 for big blades, swords and springy tools that must flex and shrug off abuse.
You are comparing 8670 vs 5160 because both steels are tough, affordable and forgiving. That is rare in the knife world. Most steels trade one strength for another.
This guide compares the two on composition, toughness, edge life and heat treatment. We also flag what the public data cannot tell you.
Who Is This 8670 vs 5160 Comparison For?
This article suits makers, hobby forgers and buyers who read spec sheets. Every figure below comes from a named source, and we mark where numbers vary.
- Bladesmiths picking bar stock for a first or fiftieth knife
- Buyers comparing fixed blades labelled 8670 or 5160
- Tool makers who want impact resistance, not a razor edge
What Are 8670 and 5160 Steel?
8670 steel in plain English
8670 belongs to the 86xx family of low-alloy steels. According to the Knife Steel FAQ at zknives.com, the family appeared during WWII to conserve nickel and other alloying elements. It is described there as a tough steel with good wear resistance, used in circular saws and bandsaws.
5160 steel in plain English
5160 is a chromium spring steel. The same steel database calls it a simple spring steel with chromium added for hardenability. It is popular with forgers, especially for larger blades.
8670 vs 5160 Composition at a Glance
Composition drives everything else. Notice the carbon gap, and notice that only 8670 carries meaningful nickel.
| Element | 8670 | 5160 |
|---|---|---|
| Carbon | 0.70–0.75% | 0.60% |
| Manganese | 0.5% | 0.7% |
| Chromium | 0.4% | 0.90% |
| Nickel | 0.85% | Not listed |
| Silicon | 0.25% | 0.30% |
Sources: 8670 figures come from a Tactical Knives column quoted on Blade Forums. 5160 figures come from Iron Flower's construction notes. Mill specs vary slightly, so check your supplier's certificate.
Carbon content, visualised
How Do 8670 and 5160 Compare Head to Head?
| Factor | 8670 | 5160 |
|---|---|---|
| Toughness | Very high, helped by nickel | Outstanding, especially at lower hardness |
| Typical knife hardness | About 58–59 HRC in the Tactical Knives column | Low 50s for swords, near 60 for knives |
| Edge retention | Good, with more carbon on paper | Good, but less carbon |
| Spring behaviour | Not its claim to fame | Leaf-spring steel by reputation |
| Stainless? | No | No |
| Best fit | Camp knives, bushcraft, hard-use tools | Swords, machetes, large choppers |
Which Steel Is Tougher?
Both are tough, so the gap is small. Machinemfg's 8670 versus 80CrV2 comparison credits nickel for 8670's toughness.
One caution applies. A Blade Forums thread notes that not all 8670 is the same. Heat treatment and the supplier change results.
5160 earns its toughness reputation another way. The zknives entry says it performs well across a wide hardness range, with great toughness in the low 50s HRC.
Which Steel Holds an Edge Longer?
On paper, 8670 has the edge. It carries more carbon, and carbon sets the hardness ceiling.
Real life is messier, because geometry and heat treatment matter just as much. Treat the difference as small, not dramatic.
- 8670: Takes a fine edge and sharpens easily, according to Machinemfg's 8670 versus 1095 write-up.
- 5160: Reaches near-60 HRC for knives that need more edge holding, per zknives.
- Both: Neither matches high-vanadium or stainless steels for wear resistance.
How Do You Heat Treat 8670 vs 5160?
Heat treatment decides whether your steel performs or just looks the part. Always follow your supplier's data sheet first.
5160 basics
- Critical temperature sits around 1525°F, per Iron Flower.
- It can reach about 63 HRC as quenched, so tempering is essential.
- Austempering at about 600°F is listed as an option.
8670 basics
- Machinemfg suggests tempering between 300°F and 450°F.
- Higher tempering temperatures add toughness and cost hardness.
- One steel supplier calls its 8670 stable in the quench, with minimal warping.
Treat supplier claims as marketing until you test your own blades. Break a few samples before you trust a recipe.
Which Steel Suits Your Project?
- Machete, sword or large chopper: Pick 5160. It is the classic choice for long, flexing blades.
- Camp or bushcraft knife: Either works. 8670 may give a slightly finer edge.
- Kitchen or EDC knife: Pick neither first. Both rust, and thin edges favour other steels.
- Hard-use tool, such as a chisel or pry tool: Pick the one you can heat treat well.
Care matters here. Redlabel Abrasives notes that 5160 lacks corrosion resistance and needs regular cleaning. Oil your blade and keep it dry.
Common Mistakes When Choosing Between 8670 and 5160
- Using old leaf springs: You cannot know the composition, so you cannot optimise the heat treatment. Forum experts prefer new steel of known grade.
- Chasing hardness: Higher HRC is not always better. Toughness drops as hardness rises.
- Assuming any "8670" is equal: Quality varies between mills and suppliers.
- Skipping tests: A hammer test teaches more than any forum thread.
What Should You Read Next?
For deeper metallurgy, visit Knife Steel Nerds. It publishes toughness and heat-treat testing.
Planning a workshop around your new steel? Our guide to smart storage for limited space helps you fit a forge corner into a small garage. Curious how spring steel works in vehicles? Read about suspension setup on lifted trucks. Like comparison guides? Try Kerlix vs Kling, which settles a very different rivalry.
Keep a first-aid kit near your grinder. Steel comparisons are fun until someone skips the gloves.
8670 vs 5160: Frequently Asked Questions
Is 8670 better than 5160?
Neither wins everywhere. 8670 suits knives that need a finer edge. 5160 suits large blades and spring-like tools.
Is 5160 steel stainless?
No. Its chromium level is too low for stainless behaviour. Clean and oil the blade after use.
Can beginners heat treat 8670 or 5160?
Yes, both are considered forgiving. Still, use a thermometer or controlled oven, and test sample pieces first.
Why does nickel matter in 8670?
Nickel raises toughness and impact resistance, according to Machinemfg. It does not add wear resistance.
Which steel is cheaper?
Prices change by supplier and region. Compare current quotes for the bar size you need.
Final Verdict
Pick 5160 for swords, machetes and long blades. Pick 8670 for hard-use knives where a finer edge matters. If you can heat treat either well, you will not regret the choice.
