All finger joints are routed with straight bits and Leigh Industries offers two variants; a two flute spiral upcut in High Speed Steel and a Solid Carbide version. The spiral upcut design cuts cleaner; faster; leaves a smoother finish and dramatically reduces tearout. Although both produce excellent results; the solid carbide versions are stiffer and they hold a keen edge longer than the HSS. Choose the bit that best suits your needs and budget.*NB: This is the Solid Carbide variant