What kind of bit should I use to cut composites like fiberglass, and glass filled polymers?
Glass filled composites are most effectively cut using a grinding action that breaks the glass and cuts the polymer binder without melting or caking. In terms of bit life and edge quality, chip-breaker and diamond cut router bits excel when machining glass filled polymers and phenolic. The limitation of this style of cutter is that they are very difficult to make to precise diameters. Typical tolerances run 0.002″. For more precise shaping, a 3 flute cutter will give acceptable performance and an excellent edge finish with somewhat reduced life (50 – 75%).
