Zone Fly Industrial and Trade Co., Ltd.

Saw Blade Components and Tip Configurations

Saw Plate
The body, which is obviously the backbone of the blade, is made from a high carbon, chrome, nickel and special moly-alloy steel. The steel will add durability by preventing warping during heat buildup and strength by absorbing initial shock pressure when cutting hard materials. Our plate tolerance is kept to less than .003 inches. Plate tolerance (side to side wobble) or "run out" of the saw blade is a key test of quality. If the plate tolerance is not kept within certain specifications, it may affect the grinding of the carbide tip or "high speed flutter" more commonly known as saw blade noise. Plate tolerance is a key factor to extremely smooth cutting in a very quiet environment.

Kerf
The width of the carbide tip measured from the two widest points of the top of the carbide tip. The kerf on a carbide tipped saw blade acts as the set in the blade giving it the clearance it needs to cut through the material

Arbor Hole
The center bore joins the saw blade with the saw. Its function is critical, for no matter how good a saw blade or saw is, if the arbor fit is not exact, neither will function at maximum efficiency. We use hand tested meters and gauges to assure the exact diameter arbor.

Diameter
The diameter is measured from the furthest edge of one tip to the furthest edge of the tip directly opposite. Generally speaking, the larger diameter blades are thought of as industrial quality for two reasons: 1) a larger diameter can facilitate more teeth for a smoother cut and 2) with a larger diameter, each tooth will have to work less and the blade will last longer as a result. We manufacture blades which range in diameter from 3-3/8" up to 18".

Gauge
The measurement of the plate thickness. Generally, a heavier plate will be stronger and more durable. The gauge goes hand in hand with the steel saw body in that a heavier plate will absorb the initial impact of the cutting edge better than a thinner plate. CAUTION: Too heavy of a plate must also be considered, as some saw machines have reduced horsepower for economical purposes and a heavy plate may tend to drag on the motor.

Shoulder
The shoulder's major functions are to add strength and support to the carbide tip. A well-designed shoulder will help strengthen and guide the carbide tip through the material being cut. Its design must be considered in conjunction with the number of teeth, hook angle, and gullet. A larger diameter blade can easily facilitate 60 to 100 teeth without sacrificing a strong shoulder design.

Gullets
The main purpose of a gullet is to provide clearance for the material being removed. The design of the gullet must be done keeping in mind such factors as material being cut, type of cut (rip or crosscut and smooth or rough), speed of the cut, type of tooth design and pitch or hook angle of the teeth. For example, a Rip saw blade is designed to cut very quickly along the grain of the wood. It has fewer teeth and a large gullet to aid in the removal of sawdust. By contrast, a Crosscut blade will have a smoother, slower cut against the grain, therefore having more teeth and a smaller gullet design. The major issue to consider in design is to have no sharp or square corners as they will lend themselves as a natural stress or fault line in the saw blade.

Hook Angle
The hook angle is the amount of forward or backward lean each tooth has. The angle is measured by the intersection of two imaginary lines. The first line is drawn flush with the face of the carbide tip and the second is drawn vertically while going through the center of the arbor hole. Basically, the greater the hook angle a blade has, the more pull or grab the blade will have on the material being cut. A rip blade has a large positive hook angle so it will cut very quickly. As the hook angle approaches zero degrees and even exceeds zero (negative hook angle), the blade exhibits no grabbing at all. This is important when cutting metals, where total control over the feed is needed.

Number of Teeth
This is one variable that will have the most noticeable effect on the cutting action of the saw blade.. As the number of teeth increases, the blade will have a tendency to cut very smoothly but slower than a blade with fewer teeth. Also, as the number of teeth increases, the distance between each tooth is decreased therefore reducing the size of the gullets making chip ejection from the gullet more difficult. This is where the design of the gullet, shoulder, tooth style and hook angles become of the utmost importance. Placing more teeth in the same amount of space can only be successful if everything matches perfectly.

Expansion Slots
The basic function of the expansion slots, which are used primarily on larger diameter blades is to create an outlet for heat buildup created during cutting. For example, imagine a 10" piece of steel with 60 or 80 carbide teeth turning at a speed of 6,000 RPM entering a piece of hardwood such as oak. A great deal of heat is built up by a combination of factors including friction, centrifugal force and the cutting material itself. Even the very best steel blade will heat up to a point where the heat is great enough to force the steel to expand. When this happens the heat (or forced expansion) must have an outlet. The expansion slots allow the steel to do just that, expand and contract without warping the steel or destroying the tension of the blade.

Expansion Slot Base Holes
The Expansion slot base holes are round geometric shapes with no sharp or square corners. A round geometric figure will take the stress of initial impact pressure from the carbide tip entering the material and disburse the pressure evenly throughout the body of the saw, otherwise the blade may crack on that stress line.

4 Types of Carbide Tipped Tooth Configurations

Carbide Tips
A carbide tipped blade will stay sharp approximately 10 times longer than an ordinary steel blade. The reason is that tungsten carbide, a man made substance, is one of the hardest materials known to man.

Square Top Tooth

Advantages:
1. It cuts both sides of the kerf simultaneously, making it twice as effective as teeth in a staggered tooth saw in which each tooth cuts only one side at a time.
2. Its balanced cutting forces reduce saw body stresses.
3. It has large included angles between cutting edges that strengthen the tooth form and keep it sharp for longer periods of time.
4. The tooth form is relatively easy to maintain.
Disadvantages:
1. The tooth form generates relatively large cutting pressure and this contributes greatly to chip out or tear out at the exit point on the material.
2. Low side clearance angles inhibit the freedom of chip flow. The chips generated in the cut drag on the side of the cut causing a buildup.

Alternate Top Bevel (ATB)

Advantages:
1. It produces very low cutting pressures that almost eliminate the tendency to tear out.
2. The chips fall free in the chip spaces created by the large side clearance angles.
Disadvantages:
1. The leading point is susceptible to wear and damage from shock loads.
2. Cutting forces perpendicular to the beveled edge result in semi-lateral thrusts on the saw body.
3. In sharpening it is difficult to maintain an equal bevel and equal diameter across the points of the teeth around the saw.

Triple Chip

Advantages:
1. Large included angles in the cutting edges give the triple chip form good wear resistance.
2. A balanced cutting force.
3. Low tooth drag.
4. Free chip flow.
Disadvantages:
1. The triple chip tooth form requires extra maintenance care to avoid the risk of changing tooth forms during sharpening. Alterations can lead to deteriorated cutting action.
2.This triple chip tooth form has strong blunt edges, there is a relatively low shear generating high cutting pressures which tend to produce chip outs.

Planer-Combination

Advantages:
1. It produces very low cutting pressures that almost eliminate the tendency to tear out.
2. The chips fall free in the chip spaces created by the large side clearance angles.
3. A balanced cutting force.
Disadvantages:
1. The leading point is susceptible to wear and damage from shock loads.
2. In sharpening it is difficult to maintain an equal bevel diameter across the points of the teeth around the saw.

Glossary of Saw Blade Terms

Anti-Kick Saw Blades: Saw Blades with anti-kickback shoulders that limit the amount of material that can safely be cut by each tooth. This virtually eliminates the kickback caused by overfeeding. Also called safety saw blades.

Anti-Stick Coatings: As used on saw blades, these coatings decrease friction and heat buildup and help provide cleaner, smoother  and quieter cutting action. Anti-stick coatings also resist resin and pitch buildup and improve safety conditions.

Arbor: The shaft, driven by the saw's motor, which turns the saw blade. Also called a mandrel.

Chipper: In dado sets, small cutting tools with varying widths. Chippers are places between the cutters, or the outside blades, of the dado set to adjust the width of the cut.

Chipping: The condition caused when the saw blade lifts and tears the wood fibers as it exits the material. This causes the edge of the cut to be ragged.

Clearance Angle: The angle between the lower face of a saw blade and the material being cut.

Combination Saw Blade: Saw blades used for both ripping (cutting with the grain of the wood) and crosscutting (cutting across the grain).

Crosscut: A cut made across the grain of the wood.

Cutoff: Refers to the smooth cutting of wood, plywood, chipboard, paneling, pressboard, etc.

Cutter: In dado sets, the two larger, outside blades.

Cutting Angle: The angle between the upper face of the saw blade and the material being cut. Also known as a rake angle.

Dado: (1) A flat-bottomed recessed cut made across the grain of a board. (2) A b> Dampener: Used to improve saw blade performance by stiffening the saw blade plate and dampening sound and vibration caused by the saw's belt, motor, and bearings. Dampeners are mounted on the saw's arbor directly next to the blade. Also called a saw blade stabilizer.

Ferrous: Of or containing iron.

Finishing Saw Blade: A saw blade with higher tooth counts to provide smoother cuts. Typically refers to 7 1/4 inch blades with more than 40 teeth and 10 inch blades with more than 60 teeth.

Framing Saw Blades: Carbide tipped saw blades used to make fast sizing cuts in all types of wood. (the fastest cutting is achieved with thin kerf saw blades.)

General Purpose Saw Blades: Saw blades with low tooth counts used for fast crosscutting and ripping in most woods and wood-related materials. This designation is commonly used with opening price point carbide blades.

Groove: A recessed cut made across the grain of the wood. A groove has two straight sides that are at a 90 degree angle with a flat bottom. See also Plough.

Hollow Ground: A concave bevel edge on a tool.

Miter: The process of cutting material for an equal angle joint.

Nonferrous: Materials and metals not of or containing iron, such as aluminum, copper, brass and lead.

Plane: In woodworking, to make a surface smooth or even.

Plough: A recessed cut made with the grain of the wood. A plough cut has two straight sides that are at a 90 degree angle to a flat bottom. See also Groove.

Precision Finishing Saw Blade: Precision sharpened saw blades with a high tooth count and thicker kerf. These blades provide very smooth cuts in hardwood, softwood, plywood, chipboard, paneling, and Marlite.

Rabbet: An open-ended cut made along the edge of a workpiece that receives or interlocks with another piece to form a joint

Ripping: The process of sawing a board in the direction of the grain of the board.

Runout: The amount of wobble in a saw blade, or how much the blade moves from left to right during use. Also called wobble or warp. Our saw blades have very little or no runout.

Shim: (1) A thin, often tapered piece of material such as metal or wood used to fill in space between things. (2) A round, usually magnetic disc used with a dado blade to provide a wider cut.

Stopped Groove: A cut made along the grain that stops short of one or both ends of the workpiece.

Tear-out: A condition in which the saw blades tears out the grain of a workpiece.

Thin Kerf Saw Blades: A saw blade with a kerf, or cut width, between .065 and .070 inches.

Worm Drive Saw: A saw that has a diamond-shaped arbor instead of a round arbor.