- Choice of circular saw blades
- Abbreviations for circular saw blade teeth
- Features of circular saw blades
- What diameter for which speed of rotation?
- Specificities of circular saw blades
- Blades with carbide pellets
- Sharpening: a work of high precision
The circular saw blades generally comprise tungsten carbide inserts brazed to teeth of different shapes. To obtain a good quality of cut, it is important to understand these forms, to change blades according to the intended use and to have them sharpened as soon as the effort to provide becomes excessive.
2. Blade body
3. Denture for metal
4. Universal teeth (wood)
5. Denture for cross cut
6. Steel serration teeth
7. Dentition for delign
8. Tungsten carbide inserts
9. Anti-lock heel
Choice of circular saw blades
The steel blade
Blades made entirely of steel with serrated teeth are the most economical, but they tend to become dull.
They are commonly used for cutting firewood.
It is necessary to privilege a step (distance between the teeth) important for a green wood and a small step for a dry and hard wood.
The diamond blade
Diamond platelets make it possible to saw very abrasive materials such as Corian or mineral-based panels.
They are recognizable by the fine black pellets that cover the carbide pads.
These blades are particularly expensive.
The nail cutter blade
This blade helps to secure the handling of recovery wood by cutting nails or any other body present without it breaking.
Alternate toothing (ALT)
Tungsten carbide pellets are brazed on the angle of attack of teeth that dull less rapidly. The top of each pellet has a bevel, oriented alternately to the right and left. This toothing is the most common for the Woodcraft. Very sharp, the external angles of the teeth make it possible to slice the fiber before removing the material.
Trapezoidal teeth (TP)
On this blade, one plate out of two is chamfered on both sides, it is the roughing machine.
The tooth that follows is straight, it's the finisher.
This type of blade allowsavoid splinters on some hard and thin materials such as melamine and laminate, as well as those based on mineral.
Abbreviations for circular saw blade teeth
The French abbreviations for the teeth (photo 1) are indicated on the packaging. ALT for alternate, TP for trapezoidal and NEG for negative. They also specify the essential characteristics, visible on certain blades (photo 2).
For example: 165 (Ø) x 2.6 (thickness of teeth or kerf) x 20 mm (bore Ø), Z = 48 (number of teeth), HW, HM or CT (tungsten carbide inserts), n. max 9,500 (maximum speed in rpm, knowing that it depends primarily on the material to be machined). The arrow indicates the direction of rotation of the blade. The other data are the manufacturer's own references.
Features of circular saw blades
The number of teeth
Blades with 10 to 80 teeth are found. The more the teeth are tightened, the better the finish.
The presence of antireculent heels on the back of the teeth (or pass limiters), aims to prevent the rejection of wood or sudden recoil of the machine.
The angle of attack
The angle of attack is positive when the tooth is bent forward and negative if it is tilted backwards. Negative angle blades are always used with radial or miter saws for cutting wood or metals. This inclination prevents the abrupt return of the blade to the user.
This term refers to the space between each of the teeth. The more important it is and the faster chip evacuation. A saw blade equipped with spaced teeth is adapted to flow works.
Straight form or question mark, the indentations allow the metal heated by friction to expand without altering the flatness of the disc. When a copper rivet is at the end of the indentations, the whistling of the blade and vibrations are attenuated (high quality blades).
This is the hole in the center of the blade that allows it to be installed on the saw motor shaft. Its diameter must be identical to that of the motor shaft. The pin holes (e) present near the bore (a) serve as a guide to correctly position the blade on the machine.
What diameter for which speed of rotation?
Specificities of circular saw blades
Continuous rim blade
This type of blade is recommended for cutting fiber cement siding. Depending on the bore and the diameter, these blades are installed either on a table saw or a radial saw.
The blades to be creased
Designed for the slat milling machine, these blades can also be used as slotting cutters.
If the diameter and bore are the same for all models, it is best to check the type of blade recommended on the machine.
The toothed reduction rings adapt the blades whose bore is greater than the shaft of the machine. They must not be thicker than the blade and have a diameter at least 10 mm smaller than that of the clamping flange.
Blades with carbide pellets
The choice of the blade is essentially dictated by the work to be done and the material to be cut. But to optimize the quality of the cut, the height of the blade must be adjusted to let only exceed the teeth of 8 mm above the piece to be cut.
Alternate bevel (ALT)
Flow and finish solid wood, chipboard, melamine, plywood
Cut composite material, wood studded, pallet, formwork board
Trapezoidal (TP) / flat
Laminate cladding, melamine, chipboard, thin solid wood
Raw panel cut, laminated panel coated (worktop), chipboard
Solid wood cutter, timber, chipboard
Steel blades hook (1); lying down (2)
Solid wood flow, firewood, lumber
Sharpening: a work of high precision
- After removing the resin residues, the sharpener uses diamond grinding wheels controlled by numerical control.
- Tungsten carbide pellets are ground on 2 / 100th mm only.
- The saw blade is constantly sprinkled with water during the operation.
- The high quality blades can be reground twenty times against two or three sharpening for basic blades.
- The sharpener is also able to burn new pellets on the teeth that have "loosened".