6.  Router Bit Failure

                                                                                                                     Steel holder                  Carbide side

Numerous holes and voids

Areas where the braze alloy did not stick to the steel

Areas where the braze alloy did not sick to the carbide

                   2

This is the corner of the carbide at 50x.   There is a brown film over the back of the braze alloy.  You can see a round area of braze alloy in the lower right.   Arrow 1 There was a trapped gas either from the flux, from zinc that came out during brazing or form another material, possible a cleaning agent.      Arrow 2 points to several bits of “gravel”.    These may be from sandblasting.   

There are large areas of bare steel.   These are most obvious in the duck shaped patches at the bottom of the first picture.  There are also several other areas.