Metal cutting band saw blade
Bandsaw blades used for cutting metal have bent teeth. The bend in the teeth creates a cut slightly wider than the thickness of the blade, which is important to prevent the blade from getting stuck from being pinched by the metal. There are 3 different blade tooth patterns: raker, wave, and straight. For most metal cutting work, use the raker pattern. But if you are cutting thin work sections, such as tubing, angles, and channels, then consider using a blade with the wave tooth pattern.
At least three teeth of the bandsaw blade must contact the workpiece at all times to prevent chatter and shearing off teeth due to tooth overload. Therefore, use fine tooth blades for cutting sheet metal and tubing. If the sheet metal is too thin for this to work with the finest tooth blade available, a useful trick is to put the metal between pieces of plywood, fiberboard, or soft thicker metal to support the blade. Our webpage How to use a BandSaw has a guide for selecting the proper pitch band saw blade for different metals and metal thickness.
The resulting finish mostly depends upon the saw pitch. The faster the blade speed and the finer the blade, the finer the finish will be. Cutting fluid also helps to improve the finish. A fine saw pitch blade, at high speed, with a light feed will produce the finest finish.
Bandsaw blades normally get dull from use, but some precautions will give you longer than normal wear on the blades. Blades will dull quickly if used at too rapid a speed for the metal being cut. Also, if the metal to be cut is too hard for the pitch of the blade, you will experience abnormal wear. The most common cause of premature blade wear comes from using too fine a pitch blade and from feeding the blade too heavy.
Symptoms indicate a dull bandsaw blade that should be replaced:
* It becomes difficult to follow a line, the blade being forced to one side or the other.
* The chips are granular (except for cast iron, which produces granular chips with both sharp and dull blades).
* The bandsaw blade cuts slowly or not at all when the workpiece is fed by hand.
* With the bandsaw off and/or the blade removed, run a finger slowly over the teeth in the direction of cut. If you do not feel sharp edges then the blade is dull.