A mitre saw is only as useful as the blade running in it. You can have a powerful, accurate machine with a good fence and a smooth sliding action, but fit the wrong blade and the cut quality collapses. Burnt edges, chipped veneers, rough grain tearout, or a blade that struggles to push through at all are the signs that the blade and material are mismatched. Here is how to read the numbers, understand what matters, and pick the right blade for the job.
---
The Numbers on the Blade: What They Actually Mean
Every mitre saw blade is described by four key figures. Getting comfortable with these turns a confusing choice into a straightforward one.
Diameter. Blade diameter must match your saw. A 216mm blade goes on a 216mm saw. Common UK sizes are 190mm, 210mm, 216mm, 250mm, and 305mm. The diameter determines the maximum depth and width of cut the saw can make.
Number of teeth. More teeth means a smoother cut. Fewer teeth means a faster, rougher cut.
- 24 to 40 teeth: ripping timber quickly, rough cuts, site work where speed matters more than a polished edge
- 48 to 60 teeth: general purpose carpentry, joinery, skirting boards, architrave, most site timber
- 80 to 100 teeth: hardwood flooring, veneered panels, MDF edges, any cut where the surface quality matters and will be seen in the finished job
Bore size. This is the diameter of the hole in the centre of the blade that fits onto the saw's spindle. Most UK mitre saws use a 30mm bore. Many blades come with reduction rings to fit smaller bores. Check your saw's specification before ordering.
Kerf. Kerf is the width of the slot the blade cuts. Thin kerf blades (around 1.8mm to 2.2mm) remove less material, waste less timber, and put less load on the motor. Standard kerf blades (2.8mm to 3.2mm) are heavier, more rigid, and suit harder materials and repeated production use. Cordless mitre saws often benefit from thin kerf blades to extend runtime.
---
Wood Cutting Blades
For most timber cutting, a blade with 48 to 60 teeth is the workhorse. It handles construction timber, PSE timber, MDF, and most sheet material in reasonable quality. A 48-tooth blade on a 216mm saw covers the majority of what a site joiner or kitchen fitter needs day to day.
For veneered board, hardwood, or any cut that goes in a visible position, step up to 80 teeth or above. The finer tooth pitch slices through the surface fibres cleanly rather than tearing them, leaving an edge that needs little or no cleanup.
Alternating top bevel (ATB) tooth geometry is the most common configuration for wood. The teeth alternate between angled left and angled right, which draws the material cleanly while keeping the leading edge sharp for longer. Most standard wood-cutting blades use ATB.
---
Metal Cutting Blades
Cutting metal on a mitre saw requires a specific metal-cutting blade. Standard wood blades will overheat, throw sparks, and potentially shatter on steel or aluminium. Do not attempt to cut metal with a wood blade.
For aluminium and non-ferrous metals, a blade with 60 to 100 teeth and negative hook angle (where the tooth leans slightly backward rather than forward) cuts cleanly without grabbing or chattering. The negative hook reduces the aggressiveness of the cut and prevents the blade from self-feeding too fast through soft metals.
For thin steel sections (thin-wall box section, angle iron, mild steel strip), dedicated ferrous metal blades with carbide teeth and very fine pitch are required. These are different again from aluminium blades and should not be interchanged.
Always check the maximum RPM rating on a metal-cutting blade and ensure it matches or exceeds the no-load speed of your saw at the relevant blade size.
---
Plastic and Composite Cutting Blades
Plastic, acrylic, uPVC, and composite decking materials require high tooth counts and slow feed rates. A 100-tooth or higher blade minimises heat buildup, which is the main enemy when cutting plastic: too much heat melts the material back onto the cut edge and can weld it to the blade.
Composite decking in particular varies in density and composition. A blade sold specifically for composites will have the tooth geometry and coating to handle the abrasive reinforcing particles that standard wood blades dull on quickly.
---
Blade Coatings and What They Do
Many quality blades carry a coating on the blade body and sometimes the teeth. Common coatings include:
- PTFE or non-stick coatings: reduce resin and pitch buildup on the blade body, keeping cuts clean and reducing drag
- Titanium or carbide coatings on tips: extend tip life on abrasive materials
- Anti-vibration slots: laser-cut expansion slots that reduce blade noise and movement at speed, particularly noticeable on large-diameter blades
A blade that stays clean and free of resin buildup cuts better and runs cooler. Resin cleaner applied to a blade that has started to leave brown scorch marks can often restore performance without replacing the blade.
---
Blade Safety
A mitre saw blade spinning at 3,000 to 5,000 RPM is a serious hazard. A few rules that are not optional:
- Fit the correct diameter and bore size. An ill-fitting blade is dangerous.
- Do not exceed the maximum RPM rating marked on the blade.
- Check for cracks, missing teeth, or damaged carbide tips before fitting. A damaged blade must be replaced, not used.
- Never use a wood blade on metal.
- Ensure the blade guard and anti-kickback mechanisms are properly in place before cutting.
- Clamp or hold the workpiece securely. Do not free-hand cuts on a mitre saw.
---