Need help w/ band sharpener adjustments

[Kelvin]

Hey just wondering how much pressure you are allowing the wheel to make with the band?  Does the grinding wheel kinda slow down when it goes through the cut?  OR just a light touch?  I take my bands off when they start following knots and not cutting straight, maybe 400 or so bd ft of oak, so they aren't trashed, but i'm getting alot of broken bands now that i'm sharpening myself. 

It seems that if i allow the band to go around about 4 times, it still doesn't come out as well as when woodmizer does them.  They don't cut as long and break.  I keep freshing up the grinding wheel and make sure i keep a good profile.  The instructions say to take more off the back of the tooth than the front, which i try to do.  Is this right?  I've started thinking i was oversetting for hardwood.  Woodmizers 9 degree blades i had bought new have .18" set each side out of the box.  I had gone from .15 for dry dead logs up to .20 and .24 for cottonwood, which didn't seem to make much difference.  i've tried setting first, and setting after grinding.  No difference. 

One thing i wonder about is how sensitive is the profile on the back of the stone?  Do you allow the tooth itself to lift the grinding wheel as it moves under it? or do you make sure the cam i picking it up before the tooth pushes against it?  I guess this goes back to how much down pressure? 

My grinding motor just barely bogs, but i have the advance speed pretty high, 3/4 of the way up or more, so the motor gets up to speed just fine.  Does this make a more coarse grind?  Doesn't appear to be much different.  Any ideas?  What do you think?  Do you make the whole band shiney, or just touch the tips, and face of the tooth?  It would take 10x's around to grind down enough to make the woodmizer grind match my stones shape perfectly. 

What do you think?  Thanks
KElvin

[Kirk_Allen]

I am no expert but this is what I found.

The grinding of the stone is VERY critical!  When I put on a new stone I turn the grinder wheel off and the rest of the unit on and SLOWLY advance the blade in automatic mode and MANUALLY roll the stone.  I try to make the CONTACT the same on the WHOLE profile. 

Some things to look at if your breaking blades.

The WHOLE profile should be dressed.  If your missing tiny cracks in the gullet its only a matter of time before they break. 

The Back of the tooth should only be barely touched, otherwise you will round out the left side of your wheel as you look at it and end up with a negative tooth angle.  (Been There Done That)

You should hear a consisitant grinding throughout the whole profile.  The back of the tooth is only getting dressed enough to knock off the burs according to the WM class I had.

Another thing to look at is the diameter of the wheel.  As it gets ground down the speed is going to change thus causing the motor to work harder to get the blade ground.

I switched to the BLUE stone that Coleman sawmill supply offers and get MUCH better results than the standard WM stone.  With the WM stone I normally take two passes.  One heavy and then one very light pass. 

[woodbowl]

Kelvin, Don't worry too much about getting the full profile, especially on a new blade. It will happen in a few sharpenings anyway as the rock conforms to the shape. I run a batch of 12 and mark each set as well as each sharpening with a die grinder. (lightly)  This is my record of history and  ensures that all the bands are the same and will fit the rock each time with very little adjustment. Be concerened with fresh grind marks on the very tip, both face and back. If it seems skimpy evrywhere else it's OK. In time it will all grind uniform. WM says, lightly kiss the face. I may do that when it's new to save the hardness, but later on I step up the kiss. No need to grind a real heavy face. You might get a Kirk Allen tooth angle. It usually takes me two rounds like Kirk unless I hit a nail. If it takes more than 2 or 3 rounds, somethings wrong. If you do hit a nail, don't grind and grind and grind. So....... It aint quite sharp. Use what you have and run everything as a set. You will get more miles out of your blades, save on grind stones and learn how to get the most out of a sharpening. I run a WM LT40/25hp Kohler, full time for 10 years now. This is my 4th motor. When I get in I'm tired and don't want to mess with blades. This system is fast! Every 3 or 4 sharpenings I set  "ALL" the blades. Sometimes things happen that cause me to deviate, but I still try to keep them as a group. If you have blades of different pitch, that will change your rock shape and not match your previous batch. I don't use WM blades in my style of sawing. They cut well but break soon. If I had a lot of power and needed to push a blade, I would use WM. I use Monkforsagar .041. I always get at least 20 sharpenings. The record to date is 42. Some people don't like them. It works for me. ;)