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JULY/ AUG 2001 IN THIS ISSUE DEPARTMENTS SURF’S UP FREE FROM SHOPSMITH FEEDBACK Copyright
2001. |
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From the Shopsmith |
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CARBIDE-TIPPED BLADES There are two primary factors to consider when deciding whether to purchase steel or carbide-tipped blades. Those two factors are cost and durability. Although carbide-tipped blades last up to 10 times longer before re-sharpening is necessary, you will typically pay two to three times as much for them as for their steel counterparts. If you use your table saw for more than an occasional cut...or if you're often cutting tough hardwoods or man-made materials such as particleboard, MDF (medium density fiberboard) or laminates...you'll be better off in the long run with carbide-tipped blades. The durability of a carbide-tipped blade comes from tungsten carbide, a powder, electronically derived from steel that's mixed with a binder material and fused under intense pressure at an extremely high temperature. The resultant incredibly hard material - Cemented Carbide - is then brazed to the steel blade. Carbide blades (5,6,7) are classified on the basis of two factors -- the grade of the carbide used in their construction -- and the grind of their teeth. Carbide is available in four grades of hardness: C1, C2, C3 and C4. The softest (C1) offers the highest resistance to shock (such as hitting a hidden nail in the wood), and the lowest resistance to wear (requiring more frequent sharpening). On the other hand, C4 carbide is the hardest and most brittle. That means it offers the lowest resistance to shock and the highest resistance to wear. You'll sharpen a C4 blade a lot less but hitting a hidden nail will most surely chip the teeth or break them off. C2 carbide is the most common grade for rip blades, while C3 or C4 are more common with crosscut and combination blades. Carbide Blade Teeth are wider than the body of the blade and typically have no set. Where the teeth on steel blades are ground on the fronts, carbide teeth are ground on their tops as well as their fronts and sides. The three most common grinds for carbide teeth are: 1 - Square Top Ground (5) for ripping wood with the grain ; 2 - Alternate Top Bevel Ground (7) for cutting with less resistance and leaving a smoother finish. Their teeth are ground to alternating left/right bevels to shear the wood fibers during the cut and sawing man-made materials ... where the smoothness of the cut is important; and 3 - Triple Chip Ground (6) for cutting man-made materials with minimal surface tear-out. Triple Chip Ground Blades feature a combination of alternate top bevel and square top ground teeth with the corners ground off. As a result, they deliver a better quality cut than an alternate top bevel ground blade. |
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