Updated: October 18, 2026 · LIZEN Sawing Knowledge
Short answer: M42 (~8% cobalt HSS tooth edge) is the standard choice for mild and structural steel, tube, profile and general workshop cutting. M51 (~10% cobalt, typically with higher tungsten and carbon) is for harder, heat-generating or abrasive materials such as stainless steel, tool steel and mold steel. Tooth hardness for both grades is typically about 68–69 HRC. Confirm the choice with a controlled sample test — not with a brochure life claim.
Already buying M42 or M51? Send one current blade specification and LIZEN will reply with the matching supply route, sample option, MOQ and production timing.
Send one blade spec
· WhatsApp +86 131 7575 3620
· sales@lizensaw.com
M42 vs M51 at a glance
Figures below use industry-typical values that align with LIZEN grades (about 8% / 10% cobalt; tooth hardness typically about 68–69 HRC). Size and tooth-form availability is confirmed per order.
| Feature | M42 | M51 | Source / status |
|---|---|---|---|
| Tooth edge steel | Cobalt high-speed steel (HSS) | Higher-alloy cobalt HSS | Industry typical |
| Cobalt content | Typically about 8% | Typically about 10% | Industry typical (LIZEN-aligned) |
| Other alloying | Typically W, Mo, V and C | Typically higher W and C than M42 | Industry typical |
| Tooth hardness (HRC) | Typically about 68–69 HRC | Typically about 68–69 HRC | Industry typical (LIZEN-aligned) |
| Heat / wear resistance | High | Higher | Qualitative; sample test decides |
| Best-fit materials | Carbon/structural steel, alloy steel, tube, profile, bundles, mixed workshop cutting | Stainless, tool/mold steel, harder alloys, demanding cuts | LIZEN brochure starting point |
| Not necessarily needed for | Production cutting of stainless, tool or mold steel | Mild/structural steel, tube/profile where M42 already performs acceptably | Selection guidance |
| Stainless steel | Can cut standard stainless in moderate sections with a correct setup | M51 variable pitch suggested | LIZEN brochure |
| Tool / mold steel | Depends on hardness and section | M51 suggested; confirm hardness, size and machine rigidity | LIZEN brochure |
| Max recommended workpiece hardness | Typically about 45–50 HRC | Typically about 45–50 HRC | Industry typical; confirm with LIZEN |
| Relative price | Standard | Higher than M42 | Quoted per specification |
| Common sizes (W × T) | Brochure references: 13×0.65, 19×0.90, 27×0.90, 34×1.10, 41×1.30, 54×1.60, 67×1.60, 80×1.60 mm | Same common sizes (confirm per grade) | Brochure; confirm per order |
| Tooth forms | Regular, hook, variable pitch | Same common forms (confirm TPI per grade) | Brochure; confirm per order |
| Coil stock MOQ | 1,000 m per material and width | Same | LIZEN confirmed |
| Welded loop MOQ | 300 loops (mixed specifications allowed) | Same | LIZEN confirmed |
| Lead time | 15–25 working days after deposit; shipping excluded | Same | LIZEN confirmed |
| Identification | Grade and spec recorded with the approved repeat order | Same | Process note |
| Break-in | Yes | Yes | Brochure + break-in guide |
What is a bimetal band saw blade?
A bimetal (bi-metal) band saw blade — also written bandsaw blade — has a high-speed steel tooth edge welded to a flexible spring-steel back. The HSS edge does the cutting and holds hardness under heat; the back flexes around the saw wheels for many cycles. M42 and M51 name the tooth-edge steel. The back, tooth form and pitch are chosen separately.
What is M42?
M42 is a cobalt high-speed steel tooth grade. It typically has about 8% cobalt, together with molybdenum, tungsten, vanadium and carbon. Cobalt helps the tooth edge keep hardness when the cut gets hot. Tooth hardness is typically about 68–69 HRC.
Typical materials for M42
- Carbon steel and structural steel
- Alloy steel and bearing steel (M42 or M51, depending on the job)
- Tube, profile and bundles, usually with variable pitch
- Mixed workshop cutting
Why distributors stock M42 as the default
Most general cutting jobs fall within M42’s range, so it is the usual grade for distributor stock and regular replacement orders. For a stock mix, M42 normally covers volume sizes; M51 is added for customers who cut stainless, tool steel or mold steel. See the M42 bimetal band saw blade product page and the distributors page.
What is M51?
M51 is a higher-alloy cobalt HSS tooth grade. It typically has about 10% cobalt, with typically higher tungsten and carbon than M42. Tooth hardness is typically about 68–69 HRC. The higher alloy content is aimed at better heat and wear resistance at the tooth edge — not a guaranteed life gain.
Typical materials for M51
- Stainless steel, including austenitic grades that work-harden during cutting
- Tool steel and mold steel
- Harder alloys and other heat-generating or abrasive materials; nickel alloys (for example Inconel) and titanium are typically recommended for M51 when grade and setup suit the job
- Production cutting under heavier load
Where M51 does not help
A higher grade does not fix a setup problem. Wrong tooth pitch, weak coolant, poor clamping, or unsuitable feed/speed can make an M51 blade fail as early as an M42 blade. Check the setup first, then the grade. Product details: M51 bimetal band saw blade.
Key differences that matter to buyers
Heat and wear resistance
In general metallurgy, more cobalt helps HSS keep hardness at higher temperatures, and more tungsten and carbon add wear resistance. That is why M51 can be more heat- and wear-resistant than M42 on hard or abrasive materials. Whether it helps on your job depends on material and setup; a controlled sample test decides. LIZEN does not publish a life figure for either grade.
Price vs cost per cut
M51 is a higher-priced grade than M42. The useful comparison is cost per cut: blade price divided by cutting area or cut count on the same job. If M42 already reaches acceptable life, M51 may not lower cost per cut. If M42 wears quickly under a correct setup, M51 is worth testing. Quotes are by specification, quantity, packaging and destination — no catalogue prices on this page.
Toughness and chipping
Tooth hardness and toughness have to be balanced. Interrupted cuts, bundles and vibration are hard on any tooth edge. LIZEN does not publish a toughness or chipping comparison between its M42 and M51. In practice, chipping on either grade most often points to pitch, feed, clamping or missing break-in.
How to choose: M42 or M51 by material
Starting points below follow LIZEN’s application matching table in the brochure. Confirm with your application data and a controlled sample test.
| Workpiece | Suggested starting blade | Selection note |
|---|---|---|
| Carbon / structural steel | M42 variable pitch | Choose pitch by cross-section. Keep at least 3 teeth in the cut. |
| Alloy / bearing steel | M42 or M51 | Suitable speed and coolant. Consider M51 if M42 wears quickly under a correct setup. |
| Stainless steel | M51 variable pitch | Lower speed, correct feed, good coolant and proper break-in. |
| Tool / mold steel | M51 | Avoid excessive feed. Confirm hardness, size and machine rigidity before quotation. |
| Tube / profile | M42 variable pitch | Finer pitch for thin walls and vibration-sensitive profiles. |
| Bundles | M42 variable pitch | Clamp firmly; control vibration. Shape and material mix affect life. |
For a size and pitch starting point, use the Blade Selector, or open the M42 and M51 product pages.
Is M51 worth the extra cost?
Use a simple decision rule:
- For general cutting (carbon, structural steel, tube, profile), start with M42.
- If M42 wears quickly, first check feed, speed, coolant, tooth pitch and break-in.
- If M42 still wears quickly on the same material under a correct setup — or you cut stainless, tool or mold steel in production — test M51.
- Compare both grades in a controlled sample test and choose on cost per cut, not on the grade name.
Setup matters as much as grade
Many short-life complaints are setup problems, not grade problems. Before changing grade, review:
- Tooth pitch: how to choose tooth pitch for bi-metal band saw blades
- Break-in with reduced feed: band saw blade break-in: why it matters
- Coolant concentration and flow: how coolant affects band saw blade life
- Tension, guides, clamping and chip removal: common reasons for short band saw blade life
Buying M42 and M51 from LIZEN: coil stock vs welded loops
LIZEN (Foshan Yihang Machinery Equipment Co., Ltd., Foshan, Guangdong, China) supplies M42 and M51 bimetal band saw blades factory-direct as coil stock and welded loops.
Coil stock for welding centers
Local welding centers can discuss M42 or M51 coil by material, width, thickness, tooth pitch, coil requirement and target applications. MOQ: 1,000 m per material and width specification. See M42/M51 coil stock for welding centers.
Welded loops
Distributors and OEM buyers can start with one repeat welded-loop specification. MOQ: 300 welded loops (mixed specifications allowed). See OEM welded loops and distributors.
Lead time and identification
Production lead time is 15–25 working days after deposit, shipping excluded, for both grades and for both coil and welded loops. For repeat supply, LIZEN records the approved blade identity, finished length and packaging requirement. To begin, see how to start a sample order or the FAQ.
How to test M42 vs M51 fairly
A grade comparison only means something when everything else stays the same:
- Same machine, same material and section, same clamping
- Same blade size, tooth form and pitch
- Same speed, feed and coolant, and the same break-in procedure
- Record cut count or cutting area, cut quality and why each blade was removed
Keep the record with the approved specification so the next order can be compared with the first.
Ready to compare grades on your own job? Send the blade you buy today and LIZEN will suggest a starting grade, sample route, MOQ and production timing.
Send one blade spec
· sales@lizensaw.com
FAQ: M42 vs M51 band saw blades
What is the difference between M42 and M51 band saw blades?
M51 has a higher-alloy tooth edge than M42. M42 typically has about 8% cobalt and suits general metal cutting; M51 typically has about 10% cobalt with more tungsten and carbon and suits harder, abrasive or heat-heavy materials. Tooth hardness for both is typically about 68–69 HRC.
Is M51 better than M42?
Not always. M51 can be more heat- and wear-resistant and costs more, but for mild and structural steel M42 is usually enough. Better means better matched to the material and setup; a controlled sample test decides.
Which is better for stainless steel, M42 or M51?
M51 is generally the first choice for stainless, especially austenitic grades; LIZEN suggests M51 variable pitch. M42 can cut standard stainless in moderate sections. Low speed, correct feed, good coolant and proper break-in matter as much as the grade.
Is M51 worth the extra money?
Worth testing when M42 wears quickly on the same job under a correct setup, or for production cutting of stainless, tool or mold steel. There is no guaranteed life gain — compare both grades in a controlled sample test and judge by cost per cut.
How much cobalt is in M42 and M51?
M42 typically has about 8% cobalt and M51 typically has about 10% cobalt. These industry-typical figures align with LIZEN grades.
Can M42 cut tool steel or hardened steel?
It depends on hardness and section. Maximum recommended workpiece hardness is typically about 45–50 HRC for both grades (industry typical — confirm with LIZEN). M51 is usually the first choice for tool and mold steel. Send material grade, hardness and size for a starting recommendation.
Can I use M51 for mild steel?
Yes, but it is often not cost-justified. M42 is the common choice for mild and structural steel, tube and profile.
Are M42 and M51 available in the same sizes and TPI options?
Common brochure sizes and tooth forms overlap; availability is confirmed per grade and order. Send the size and TPI you buy today.
What does bimetal mean?
A high-speed steel tooth edge welded to a flexible spring-steel back. M42 and M51 refer to the tooth-edge steel, not the back.
Do M42 and M51 need break-in?
Yes. Run new blades with reduced feed first. See the break-in guide.
Which grade lasts longer, M51 or M42?
There is no published LIZEN life ranking. On hard, heat-heavy or abrasive materials under a correct setup, M51 is often the better match; on general steel work, M42 is often enough. Compare with a controlled sample test.
Can I mix M42 and M51 in my stock?
Yes. Many distributors stock M42 for volume sizes and add M51 for stainless, tool and mold steel customers. See distributors.
Which grade should distributors stock first?
Start with M42 for the sizes your customers reorder most. Add M51 when you have regular stainless, tool or mold steel demand — or when customers report short M42 life under a correct setup.
What is the MOQ for M42/M51 coil and welded loops from LIZEN?
Coil: 1,000 m per material and width. Welded loops: 300 loops (mixed specifications allowed). Lead time: 15–25 working days after deposit, shipping excluded.
How do I get a quote for M42 or M51 blades?
Send one current blade specification: length × width × thickness, tooth pitch, cutting material, machine model, monthly volume and destination. Use the RFQ form, WhatsApp +86 131 7575 3620, or sales@lizensaw.com. Prices are quoted per specification, quantity, packaging and destination.
Send one blade specification
You do not need a full catalog to start. Send the details below for the blade you buy today — by RFQ form, WhatsApp or email. Photos of the machine nameplate and the current blade package help.
What to send LIZEN (RFQ checklist)
- Blade size: length × width × thickness (for example 34 × 1.1 × 4115 mm)
- Tooth pitch (TPI) and tooth form, and the grade you use now (M42 or M51)
- Material and hardness, if available
- Shape: solid, tube, profile, bundle or bar
- Cutting size and wall thickness
- Machine model
- Monthly volume, coil or welded loops, destination country and packaging request
WhatsApp template:
Hello LIZEN, I need help choosing M42 or M51.
Blade size (L x W x T):
TPI / tooth form:
Current grade:
Material and hardness:
Shape and size / wall thickness:
Machine model:
Monthly volume (coil or loops):
Destination country:
Packaging request:
Send one blade spec
· WhatsApp +86 131 7575 3620
· sales@lizensaw.com
The LIZEN M42/M51 brochure is in the Download Center. More short answers: FAQ.