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Bahco and Morse, UK stock

Bi-metal bandsaw blades

An HSS tooth edge on a fatigue-resistant alloy backing: the blade fabrication and engineering shops fit as standard. Choose M42 or M51, pick your pitch and we weld the band to your machine's exact length.

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Two steels doing two jobs

A bi-metal blade solves a contradiction. Teeth hard enough to cut steel are too brittle to survive flexing around a bandsaw's wheels, and a band springy enough to flex all day is too soft to hold an edge in metal. The construction answers both at once: a narrow strip of high speed steel, commonly M42 or M51, is welded along a fatigue-resistant alloy steel backing, and the teeth are then milled so only the tips are high speed steel. The edge keeps its hardness at the temperatures steel cutting generates, while the backing absorbs the constant bending that would crack a through-hardened band.

That split is why bi-metal is the default in fabrication and engineering workshops. One construction covers aluminium, brass and copper, mild and structural steel, stainless and tool steels, cast iron and even abrasive timber where carbon steel blades blunt too quickly. The choices that remain are the edge grade and the tooth pitch, and both are dealt with below.

M42 or M51: choosing the edge

Every blade in this range pairs one of two high speed steel edges with the same style of alloy backing. M42 covers most workshops; M51 exists for the work that wears M42 out. When even M51 struggles, the next construction up is a carbide-tipped blade.

M42 against M51, drawn from the manufacturers' published positioning. Both weld to the same backing; the difference is the edge.
ConsiderationM42M51
Edge materialCobalt high speed steel.High speed steel carrying more tungsten.
Behaviour under heatKeeps its hardness at the temperatures generated when cutting steel, so the edge cuts rather than rubs as the work heats up.Holds hardness further into hot, abrasive cutting; the margin tells most on long cuts through large solid sections.
Wear behaviourOutlasts carbon steel teeth many times over on ferrous work.Wears slower again on tough, abrasive ferrous material where M42 edges dull early.
Typical workThe everyday fabrication mix: steel, alloy steel, stainless steel, iron and non-ferrous metals.Tempered steels, larger solid sections and some exotic alloys, including titanium.
When to choose itStart here. It is the default edge for general fabrication and engineering.Step up when M42 blades wear quickly on tough ferrous material rather than failing from fatigue.
In this rangeMorse M42 from M.K. Morse; Bahco's Sandflex Cobra Foundry blade also carries M42 tips.Premium powder-HSS edges such as Bahco's King Cobra PHX take the step up for large, tough and difficult alloys.

What bi-metal blades cut

The materials below come from the manufacturers' published ranges for this construction. The guidance is general: section size, machine condition and feed discipline matter as much as the material name.

Typical bi-metal workpieces with general cutting guidance. Material names link to our dedicated guides where one exists.
MaterialCutting guidance
Structural steelBox, angle and beam are interrupted cuts through thin walls. Choose a finer variable pitch so several teeth share each wall, and keep the feed steady where the blade breaks through a face.
Mild steelSolid bar wants a coarser pitch with gullet room for a full chip. Feed positively so every tooth bites; a blade allowed to rub polishes the cut face and dulls itself.
Stainless steelWork hardens the instant a tooth rubs instead of cuts. Bite from the first pass, never dwell in the cut and keep the coolant generous.
Tool steelAnnealed grades saw respectably on premium bi-metal with a firm feed and an unhurried band speed. Hardened material is carbide territory rather than a job for HSS teeth.
AluminiumFast cutting but gummy. A coarse pitch keeps the gullets clear of packed swarf, and a sharp blade with a steady feed stops the soft alloy smearing onto the tooth face.
BrassUsually free cutting with short chips. A medium pitch and moderate feed give clean faces; ease the feed on thin sheet so the teeth do not snatch.
CopperSoft and gummy rather than hard. Keep the pitch on the coarse side for the section and change the blade while it is still sharp: a dull edge tears rather than cuts.
Cast ironThe skin is harder and more abrasive than the core, so feed firmly through it rather than easing in. Expect powdery swarf and follow the machine guidance on cutting dry or with coolant.
WoodWhere carbon blades blunt too quickly, for example abrasive hardwoods and high-output resawing, a wood-geometry bi-metal edge keeps its point far longer between changes.

Picking tooth pitch and width

Width first: fit the widest band your machine will tension properly for straight, deep cuts, and only go narrower when the work curves. Pitch then follows the section you cut, not the material's name.

  1. Measure the section

    Measure the metal the teeth actually pass through: wall thickness on tube and box, full width on solid bar. The thinnest part of the cut governs the pitch.

  2. Apply the teeth-in-cut rule

    Aim for between 4 and 24 teeth in the cut at any moment. Fewer and each tooth takes too big a bite and can strip; more and the gullets fill before they clear, so the blade rubs.

  3. Coarse for solids, fine for walls

    Big solids run coarse, with variable pitches in the 2/3 to 4/6 TPI range, so the gullets can carry a full chip. Thin wall tube and profiles run finer, such as 8/12 or 10/14, to avoid tooth strippage.

  4. Mixed work runs variable

    A variable pitch band covers a spread of section sizes and breaks up the vibration a fixed pitch can set off, so one blade handles a varied cutting list without constant changes.

Each product page lists that blade's published width and TPI options. If you would rather answer three questions than read a chart, the blade wizard applies the same rules for you.

The bi-metal range

17 blades from Bahco and Morse with published widths from 6 to 80mm, every one welded to the length you order.

Shop all bi-metal blades

Industries that run on bi-metal

Where this construction is the first blade on the saw, and where it works alongside carbide for the hardest jobs.

Material guides for this range

From the blog

Frequently asked questions

Tell us the length your machine takes and we will weld your bi-metal blade to match.

Order a custom length