"Peter Hyde" wrote in message
...
Sometimes the harder guides like ceramic tend to case harden the blade
especially if there is unevenness in the weld or they are set too close.
As the case hardening occurs it causes the area around the weld to
become brittle and the constant bending around the wheels causes
failure. 3 wheel machines also tend to break welds because of the
smaller radii of the wheels.

The ceramics are so frictionless that there isn't a chance to build heat.
Unless someone's been roughening yours, and it'll take some real abrasive,
not going to be the problem.

Not to mention, they don't wear as the blade tries to wander out from the
center of the circle you're cutting. Wear on softer cool blocks in these
circumstances can allow twisting of the blade, with premature consequences
of breakage.