M51 Bimetal Band Saw Blades — Selection Guide
Ready to order? See M51 bimetal band saw blades — sizes, MOQ and factory pricing
What M51 is for
M51 is the heavy-duty bimetal band saw blade for hard-to-cut material: stainless steel, tool and die steel, high-alloy steels, and high-volume cutting of large sections. The tooth tip is high-cobalt high-speed steel (about 68–69 HRC) on an alloy spring-steel back, for long life where M42 wears too fast.
How to choose in 3 steps
- Material first — pick the grade. Stainless steel, tool steel and die steel take M51. Carbon and structural steel take M42. See the material table below.
- Workpiece size — pick the TPI. The tooth pitch follows the size of the material being cut, not the blade width. Keep at least 3 teeth in the cut at all times, and no more than about 24. See the size tables below.
- Machine — pick the width. Use the widest blade your machine takes that still fits the cut. The width table below shows which tooth pitches are available in each width.
Available widths and tooth pitches (TPI)
TPI is chosen by workpiece size, not by blade width. This table shows which pitches are available in each width — it is an availability table, not a recommendation. M51 is made in coarse pitches only: 0.75/1.25 to 4/6. Fine pitches (5/8, 6/10, 8/12, 10/14) are not produced in M51 — use M42 for fine-tooth work.
| Blade size — width × thickness (mm) | Variable pitch (TPI) | Constant pitch (TPI) |
|---|---|---|
| 13 × 0.65 | — | — |
| 19 × 0.90 (3/4″) | — | — |
| 27 × 0.90 | 0.75/1.25, 1.4/2, 2/3, 3/4 | 1.25 |
| 34 × 1.10 | 0.75/1.25, 1.4/2, 2/3, 3/4 | 1.25 |
| 41 × 1.30 | 0.75/1.25, 1.4/2, 2/3, 3/4 | 1.25 |
| 54 × 1.60 | 0.75/1.25, 1/1.5, 1.4/2, 2/3 | 1.25 |
| 67 × 1.60 | 0.75/1.25, 1.4/2, 2/3, 3/4 | 1.25 |
| 80 × 1.60 | 0.75/1.25, 1.4/2, 2/3, 3/4, 1/1.5 | — |
19 mm (3/4″) and 20 mm are the same size class. M51 is not made in narrow widths — fine-tooth sizes and small sections take M42. Typical availability — confirm per order.
Choose TPI by workpiece size
Solid bar — by diameter / cutting width.
Start with the pitch below, then check that at least 3 teeth are in the cut. Pitches of 5/8 and finer are shown for reference only — M51 is supplied in coarse pitches only (0.75/1.25 to 4/6). For thin-wall and small sections, use M42.
| Workpiece size | Starting TPI |
|---|---|
| Up to 2.5 mm | 14/18 (M42 only) |
| 5 mm | 10/14 (M42 only) |
| 7.5 mm | 8/12 (M42 only) |
| 10 mm | 6/10 (M42 only) |
| 12.5 mm | 6/8 (M42 only) |
| 15 mm | 5/8 (M42 only) |
| 17.5–20 mm | 4/6 |
| 22.5–25 mm | 3/4 |
| 50 mm | 2/3 |
| 125 mm | 1.5/2.0 |
| 250 mm | 1.4/2.0 |
| 375–500 mm | 1.0/1.3 |
| 625 mm and above | 0.7/1.0 |
Tube and thin-wall profile — by wall thickness.
For tube, count 2–3 times the wall thickness as the contact length. Thin-wall tube takes fine teeth — use M42.
| Wall thickness | Starting TPI |
|---|---|
| 1–2 mm | 10/14 (M42 only) |
| 2–4 mm | 8/12 (M42 only) |
| 4–8 mm | 6/10 (M42 only) |
| 8–12 mm | 5/8 (M42 only) |
| 12 mm and above | 4/6 |
When in doubt between two pitches, choose the finer one — especially on thin-wall tube. Soft material such as aluminium cuts best about two pitches coarser than the table value.
Choose grade by material
| Material | Recommended grade | Notes |
|---|---|---|
| Carbon steel / structural steel | M42 | Variable pitch |
| Alloy steel / bearing steel | M42 or M51 | M51 for harder alloys and higher volume |
| Stainless steel | M51 | Variable pitch |
| Tool steel / die steel | M51 | — |
| Tube and profile (thin wall) | M42 | Variable pitch, fine tooth |
| Bundles / mixed sections | M42 | Variable pitch |
| Aluminium, copper, brass | M42 | Standard tooth |
| Cast iron | M42 | — |
| Wood, plastic, composites | M42 | Standard tooth |
Tooth forms
Standard tooth
Straight tooth face, 0°, 7° and 10° rake angles, even pitch and a deep gullet. The general-purpose form, most commonly used for all general-purpose metal sawing.
Profile tooth
Reinforced back reduces the risk of broken teeth. Designed for steel construction and industrial profile cuts, with good strength and powerful cutting ability. Only available in 3/4 and 4/6 TPI, with 7° and 5° rake angles.
Double tooth
Reinforced double-tooth design for steel bar cutting, with a unique tooth profile for powerful cutting. Designed for cutting steel bar, especially reinforcing steel bars.
Ordering
Trial order: 300 loops (mixed specifications allowed). Coil: 1,000 m per material / width specification. Samples available.
Send us your material, workpiece size and machine width — we confirm the tooth pitch before quoting.