Expertise · Know-how

Circular saw know-how: sharpening and maintaining circular saw blades

Carbide-tipped or stellite-tipped: a circular saw blade runs at high speed and only cuts cleanly if every tooth is ground exactly the same. Here we explain the steps in the filing room, from incoming inspection to automated processing, with tips from more than 80 years of practice.

The process

From dull to ready-to-use

  1. 01Cleaning and incoming inspection
  2. 02Stellite tipping and re-tipping
  3. 03Top and face grinding
  4. 04Side grinding
  5. 05Automation
  6. 06Measuring and inspection

For carbide-tipped blades, top and face grinding and side grinding are the core. Stellite tipping applies to stellite-tipped circular saw blades. Cleaning and inspection belong to every cycle.

01Cleaning and incoming inspectionEvery blade is cleaned and checked for damage before sharpening.

Why it matters

Resin and dirt distort probing and measuring. Damaged teeth, cracks in the saw body or a distorted blade must be detected before time and abrasives are invested.

Practical tip

A clean blade is the prerequisite for accurate measurements. In automated systems, cleaning is often the step with the greatest influence on quality.

How it works

  1. Clean resin and chips from the blade
  2. Check teeth for chipping and missing tips
  3. Check the saw body for cracks, runout and tension
  4. Sort out blades that need repair
02Stellite tipping and re-tippingOn stellite-tipped circular saw blades, a wear-resistant cobalt alloy is welded onto each tooth tip. Missing carbide tips are replaced.

Why it matters

An intact, hard cutting edge on every tooth is the basis for service life and an even cut. A single missing or undersized tooth overloads all neighbouring teeth.

Practical tip

After re-tipping, grind all teeth to the same height and projection, otherwise individual teeth work harder than others.

How it works

  1. Clean and position the tooth tip precisely
  2. Weld on stellite automatically
  3. Braze replacement tips on carbide blades professionally
  4. Then grind new tips to size

Matching ISELI solutions

03Top and face grindingThe actual cutting edge is created at the tooth face and the tooth top.

Why it matters

Hook and clearance angles determine how easily the blade cuts, how much heat is generated and how long the edge lasts. Deviations from tooth to tooth cause runout errors and an unsteady cut.

Practical tip

Diamond wheels are used for carbide, CBN wheels for stellite. Remove a little regularly rather than a lot rarely: this protects the edge and extends blade life.

How it works

  1. Define tooth geometry and angles or load them from memory
  2. Probe and index the teeth automatically
  3. Grind face and top with defined stock removal
  4. Take the tooth sequence into account for alternate top bevel or triple chip

Matching ISELI solutions

04Side grindingThe side clearance faces of the teeth are ground and brought to exactly the same kerf width.

Why it matters

Even sides with the correct side angle ensure clean cut surfaces and a straight run, and prevent the blade from rubbing and heating up in the cut.

Practical tip

Side grinding is not needed at every sharpening, but at the latest when the kerf width decreases through top and face grinding or the cut surface becomes rough.

How it works

  1. Define radial and tangential angles
  2. Grind both sides of every tooth symmetrically
  3. Measure kerf width and tooth projection

Matching ISELI solutions

05AutomationRobot-assisted loading systems process circular saw blades without an operator, also overnight and at weekends.

Why it matters

Large sawmills change many blades every day. Automation ensures consistent quality, relieves skilled staff and uses the machines around the clock.

Practical tip

You do not have to start big: a single machine with a robot and two loading trolleys already relieves the filing room noticeably and can be expanded later.

How it works

  1. Place blades on loading trolleys
  2. The robot loads sharpening and side grinding machines
  3. Integrated measurement checks every blade
  4. Rejects are sorted out automatically

Matching ISELI solutions

06Measuring and inspectionAfter sharpening, angles, tooth height, kerf width and runout are checked.

Why it matters

Only measured values are reproducible. Documentation per blade shows how often it has been sharpened and when it needs replacing.

Practical tip

Machines with an integrated measuring system check every blade automatically and save the separate measuring step.

How it works

  1. Measure tooth height and runout
  2. Check kerf width and angles
  3. Check the remaining length of the tips
  4. Record values for each blade

Matching ISELI solutions

Typical faults

From symptom to cause

Most problems show up in the cut, in the noise or on the blade. The cause often lies in the filing room.

Rough or torn cut surface

Possible causesDull teeth, uneven tooth height, wrong hook angle

Action in the filing roomResharpen in time, even out tooth height, check geometry

Blade gets hot, burn marks on the wood

Possible causesKerf too narrow, sides rubbing, dull edges

Action in the filing roomRegrind the sides, check side angle, sharpen the edges

Loud or unsteady running

Possible causesRunout errors, uneven teeth, tension in the saw body

Action in the filing roomMeasure runout, grind all teeth equally, check the saw body

Tips chip off

Possible causesWedge angle too small, foreign objects, overheating during grinding

Action in the filing roomAdjust angles, reduce stock removal, check cooling

Cut wanders

Possible causesUnequal kerf width left and right, distorted blade

Action in the filing roomGrind sides symmetrically, check flatness

Short service life

Possible causesUnsuitable geometry, excessive stock removal, wrong grinding wheel

Action in the filing roomMatch geometry to the wood species, choose a suitable diamond or CBN wheel

Your filing room, our know-how

Want to automate the sharpening of your circular saw blades or facing a problem not listed here? Send us a photo of the blade or the cut surface.

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