Tungsten carbide or simply “carbide” is three times harder than steel, and when placed on saw blades, cuts cleanly through steel. Tungsten carbide is one of the hardest compounds found naturally and used to produce a long wearing, heat and scratch resistant material when combined or cemented with other materials.

While the benefits are well known, what should you look for when selecting the best carbide-tipped band saw blade for the application at hand?

• Blade solutions for exotic sawing are useful for addressing cutting challenges such as harder materials including nickel and special alloys. For example, for very hard materials, a carbide-tipped blade with a multi-chip grind and high-low sequence produces more chips spread out over more teeth, offers faster cutting to maximize productivity and blade life.

In addition, look for blades that offer a “backgrind” technology. For example, AMP technology available from Starrett features a custom back edge enhancement on the blade which generates a rocking motion while cutting, further enhancing tooth penetration while reducing feed pressure. This cutting motion also serves to minimize surface contact area, increasing the blade life on hard-to-cut alloys.

• Pay attention to factors such as pitch, blade width and tooth set design.

Blade pitch, defined as the number of teeth per inch (25 mm), needs to be properly selected. The number of teeth that come in contact with the work can affect both blade performance and durability. Too few teeth in contact with the work can lead to early tooth strippage. Contrastingly, too many teeth can greatly reduce cutting rates and ultimately make the material impossible to cut.  At lower cutting rates there is less penetration per tooth, causing more rubbing than cutting, which can result in substantial work hardening of the material.

A constant pitch blade (uniform distance from one tooth tip to the next tip) can increase harmonic vibrations. Harmonic vibrations can lead to excessive noise, undesirable saw or saw blade vibrations and in severe cases, bad cuts.  When considering the tooth pitch for the blade, variable-pitch blades can greatly reduce harmonic vibrations.  By varying the tooth spacing, sawing rhythms are interrupted, chip evacuation is improved and vibration is reduced, resulting in less noise and a better overall cut.

Consider whether constant or variable pitch is best. With constant pitch, all teeth on the blade have uniform spacing, gullet depth and rake angle throughout the full length, which is typically for general purpose cutting. Variable pitch teeth have varying tooth sizes and depth of gullets, to substantially reduce noise levels and vibrations. The latter cuts all structurals, tubing and solids smoothly and quickly.

For Blade Width, all production type saws or any saw that is capable of running carbide blades will be designed to work with one size (width) blade.

Tooth set is the side-to-side bending of the teeth, left and right. This provides clearance for the blade to move through the cut by helping to clear chips. In addition, the tooth set can affect how efficiently the blade cuts and the quality of the resulting surface finish.

• Partner with a reputable saw blade supplier or manufacturer who has blades that address today’s sawing challenges. Materials are continually evolving, so blade design and manufacture needs on-going research and development to fine-tune, upgrade and keep up with changes. A good research and development process collects data during every test and uses it to troubleshoot and determine any necessary adjustments to blades. If a blade is not cutting effectively, testing continues until the blade works as intended. The process to perfect a new product can take up to five years from drawing board to market.

• Real world application examples offer insights that can help when selecting the right carbide-tipped blade. Recently, a customer cutting primarily titanium had a challenge with their current blade “dulling out” quickly, leaving crooked cuts and a rough finish. With the assistance of a Starrett saw specialist and implementing the Advanz MC5 Carbide-Tipped Blade, blade life was increased by approximately 30% and the finish was improved, while maintaining a high production rate.

Another customer was cutting very large forgings and having production issues, unable to keep up with their milling machines. By introducing the Starrett Advanz MC7 Carbide-Tipped Blade, they were able to keep the milling machine in full production, without putting stress on the blade and significantly extending blade life.