Tips to Identify Metal Circular Saw Blades

If you want choosing a circular saw blade to cut metal is just as important as choosing one for your woodworking projects. The right blade will give better quality cuts and last longer making them a better value in the long run.

• Decide if you want to use a carbide toothed blade or an abrasive blade. Abrasive blades are cheaper but they wear out much quicker and you may need more than one to complete the jobs.
• Verify the size of the arbor on your saw. Most 7-1/4" circular saws have an arbor of either 5/8" or 13/16".
• Verify the type and thickness of the metal you are cutting. Different blades are designed to cut different types of metal and the information is generally printed on the face of the blade along with the size and arbor diameter information.
• If the printing has been worn off another way to identify metal cutting blades is by the angle of the carbide tooth. Carbide teeth on metal cutting blades usually either have no angle or are angled slightly backward.

source by ehow.com

Part of Saw blades

The saw blade – irrespective of how good the saw is, how flat the table, how rigid the fence, if your saw blade is substandard, everything else is cheapened. The blade tends to be somewhat overlooked (ok a bit of a generalisation), as it just seems to keep going and going and going. What it is however, is a series of tiny chisels. A hand chisel gets looked after, cleaned, sharpened and stored correctly, and the saw blade should receive the same attention.

These days, the blade is often laser cut from high carbon alloyed steel, with the cutting edge being a Tungsten Carbide Tip (often a Tungsten-Cobalt alloy) The tip is very hard, but brittle, and is brazed onto the body of the blade. It is used because it will retain its edge for about 10 times longer than steel. The width of cut (the kerf) is primarily the width of the Carbide Tip, although there are other factors that come into play. In general, the kerf is 3mm, but there are also thin-kerf blades which are good for minimising wastage, and to get better performance out of lower-powered saws.

During the cut, the tips are cutting or peeling wood away, and to allow it to get away from the cutting edge, a gullet is provided below the TCT. The size of the gullet dictates what the blade is for. Crosscutting requires a small gullet, and consequently a much higher tooth count is possible (the number of teeth on the blade). The more teeth, generally the smoother the cut. However, when ripping (down the length of the board), this is an easier operation, and so you don’t need as many teeth for a good finish. Lucky, because the operation also generates significant amounts of shaving, and you need a much larger gullet. (Obviously once the tooth is clear of the wood, the gullet is free to empty) If the gullet clogs during the cut, cutting performance is seriously restricted, it becomes much harder on the saw, and the wood is much more likely to overheat and burn.

The operation generates quite a bit of heat, and to stop the large disk of the blade warping, expansions slots are provided. They are also called noise reduction slots, but in the end, noise would be caused because of the speed of the edge of the blade (up to 200km/hr), and any distortion of the disk will significantly increase that noise. Distortion of the disk is far more important for other reasons – rougher cut, wider kerf, and really, I don’t want a distorted disk spinning that fast. I don’t see noise as being as big a deal (especially in a circular saw – the noise of the saw is significantly more than the blade.) This may not be so true on the quieter saw tables, but I haven’t experienced them enough to say where the primary noise is being generated.

At the end of the expansion slot is a cut circle. This is sometimes filled with solder (to reduce noise), but the function of the hole is not affected. It is there to stop the expansion slot growing (and if it grew, the blade could literally fall into 2 pieces, or fly in 2 pieces!) The end of a crack is a major stress raiser, and an expansion slot is just a deliberate crack – it needs the same treatment to prevent disaster. This same technique is used to stop cracks in glass growing – drill a hole at the end of the crack, and the crack is arrested.

Some blades (particularly ripping blades) have a feature on the back of the tooth to decrease the likelihood of a kickback. To be honest, I don’t know how effective they would be – after all the majority of kickbacks happen at the rear of the blade, catching and throwing the workpiece, rather than the saw trying to eat more than it can cut.

There are some different ways that the teeth can be set, and I’ve only got a couple of examples here. The first is an alternating top bevel. This cuts (or slices) left, then right, making for a smooth cut, which is like running a sharp chisel down either side of the cut.

The second is called a triple-chip blade (I think incorrectly – because the raker tooth is full width, and doesn’t have the corners removed). I think it is actually known as a Planer-Combination, with a left cutting tooth, a right cutting tooth (as is the case with the alternating top bevel blade), but then has a raker tooth, which removes the v-shaped piece left in the middle from the alternating teeth. This results in a much smoother bottomed cut.

Source by www.stusshed.wordpress.com

Setting Height of Saw Blade

Setting height of the saw blade on the machine is very important to produce a good piece of Aluminum, while the distance of the height setting is a good chainsaw :
1. Tipped of Saw blade out of the object in a piece is 3 to 6 mm
2. Setting the saw blade must be done on both spindle machine (Right spindle and Left spindle)

Note : A = 3 mm ~ 6 mm
B = Thickness of Aluminum
C = A + B

Sharpening carbide tipped circular saw blades

Select a well-lighted working area for cleaning and sharpening your saw blade. Ensure that the working surface is clear of any dust, dirt or other debris.
Fill the basin with hot water and add generous amounts of citrus oil soap until the surface is thick with soapsuds. Submerge the dull saw blade in the basin and let soak for 10 to 20 minutes to loosen any resins or oils trapped between the blade teeth. Once finished, carefully scrub the faces and teeth of the blade using a small brass-bristled brush. Rinse the blade in hot water and let dry.
Put on your safety gloves and goggles. Insert the diamond paddle hone attachment into the Dremel tool and wet the tip in soapy water. Turn the Dremel tool on the medium setting and apply the wet paddle hone tip to the flat steel faces of your saw blade. Wet the paddle hone attachment periodically as the liquid evaporates, or if sparks occur. Continue working the faces of the saw blade until both surfaces display a uniform sheen and color.
Position the saw blade for sharpening by holding the blade vertically with one gloved hand. Dip the paddle hone attachment in soapy water once more and carefully insert it against the flat, "leading" face of the saw teeth. Turn the Dremel tool to the medium setting and apply the wet hone to each carbide tooth, making sure to keep the hone flat against the face of each tooth so as to protect the sides of the teeth. Finish each tooth by gently pressing the hone to the top of each tooth, to aid in cutting.
Repeat until each tooth of your carbide saw has been successfully sharpened. Rewet the paddle hone attachment as necessary if sparks occur. Once sharpened, rinse the blade again and let dry.