In my case (I've only been woodworking for 1.5 years) I was stupid enough to
run some MDF on my jointer. Since then I've learned that not only are there
harsh glues in MDF you also get bits of rock and other crap. Ugh.

Needless to say I have some minor (they are minor) nicks in my knives now --
very easy to see on the wood, you get nice little inverted grooves (probably
2 thou. wide is all -- but they're visible). I was trying to slide one of
my knives perpendicular to the tables (sideways I guess you could say) so
that the nicks no longer line up and hopefully remove some of the grooves as
a result.

Mike


"Brian in Vancouver, BC" wrote in message
news:rqnPb.59337$De.19730@edtnps84...
I have had my jointer for about 3 months now and have not yet had to
change
the blades. When do you decide it's time to make a change (replace/flip
them)? About how much wood does a blade handle (feet of material)? I
realize that the hardness of the material will make a difference. I am
using Ulmo (sp?) which is softer than maple I believe. Do I look for
certain marks or shininess on the surface?

Brian