Hook Angle - Blade Tension

[highpockets]

Guys and Gals, I know we have beat this old horse death, but please console an old man.  Yesterday I had the opportunity to go down the road and watch a milling operation.  Although I built a band mill several years ago, I had only seen one run before and that was a one log cut demo.   

The old man (88 years old) was running a WM40-24.  He was cutting what I believe was either 16' or 20' Pine Logs.  There was a penciled in 20' marker at the end of the mill and the mill was full of log.  He'd load a 20" diameter log, measure out what he could get and slab off for a cant.  Then he'd cut 2x4's and 2x6's. 

After I watched a couple of cuts, I started looking for the blade walking in the knots. Of course these were nicer logs than I have had anything to do with lately, there was very little deviation on the knot. I mean this was some good sawing.  The first thing I did was time the feed rate. It took him 90 seconds to make a run down the log.  I figured this is some 13.33 ft/min.   

When I commented to him about how nice the cut was, he told me that it was mostly in the angle of the hook and set.  He said run plenty of set. Since we had been running 3/4 blades I measured his thinking he was running a 7/8 blade.  No, he had a 3/4 just like we run.   He told me he sharpened his own blades and I was welcome to look at some in his truck.  Although I did not have my machinist protractor, I will say that he did not have over 6 degrees of hook.  I could not tell the total set either.  I also noticed that the gullet was not radiused as much as a new blade either.  Although this is somewhat contrary to what I read, I saw what I saw.   

His blade tension gauge pretty well stayed at 2,100 give or take 100 either way.  One of my questions to the WM Owners, is how much actual tension does this equate to.  I could not get to the tension cylinder to caliper it's diameter.   One thing I noticed is that he did not run his blade guide out to the log at anytime.  It just cut nice wood. 

One thing I did notice was as the saw fed along the log, if it approached a knot, it seemed to stall a little and then continue.  Man, this electric drive is something.  I have come to the conclusion that I am trying to feed to fast and may not have as much control of feed pressure as I should.  I'd like someone's comments on this.

This was a very valuable learning process for me.  I appreciate any input you real sawhands have.  The more I see, the more questions I have. 
Thanks

[Kelvin]

I too sharpen my own woodmizer blades with an old woodmizer sharpener.  From my experience i have found a wide set increases the quality of cut in pine.  I use one blade for everything i saw, its a standard woodmizer blade with 9 degree hook, 7/8" pitch.  I simply write on each blade what it is for.  Pine or oak.  the wider the cut, less set.  Pine sawdust expands 3x's when it is cut from the log by the tooth.  Too much sawdust spilling out of the gullets before it is out of the log creates heat, and dulls quickly.  Its amazing how much difference the same blade with different set makes.  I would like a different pitch for soft wood, though i'm not going to reset the sharpener for each blade, so my system works.  i use .018 set on hardwoods, (each side) and .022 or more for pine.  Wandering blade means its time to take off and sharpen.  The most blades i actually break are in pine when a dulling blade is pushed to far and hits those hard knots.  Its much more sensible to pull the blade when you see wandering.  Hardwood sawdust doesn't expand as much as pine, but if the cut is wide you will have the same problem, hence reducing tooth spacing, and hook, in wider cuts.  Woodmizer sells their 4 degree blades for cuts wider than 16".  Narrow set also helps.  I've tried 4 degree hook and it helps as well.  Watch your cant as you cut.  80% or more of the sawdust should be removed with only a light dusting left on the cant after you have removed your board.  ANymore and you need to change something, hook, pitch, set.  You name it.  Once in awhile i will get a blade just perfect for the conditions.  Don't know what is different, but that blade will offer no resistance.  just sail through oak with ease.  It will slow down in a little while, but i can tell that if you get everything just right, Wow!
Good luck.  Try some things.
KP

[jpgreen]

Ahhh... the artistry of the band blade.  Sounds like playing a fine instrument to me..  8) 8)

Got to learn yo axe..   ;D

[highpockets]

Kevin,
Thanks for the input.  First I'd like to say we are running Lennox Woodmaster C blades. They are 3/4 pitch blades.  I been buying from smith sawmill service simply because I can go to East Texas and pick them up.  One thing I have noticed that we leave a lot of sawdust on the log.  We do run a lot of diesel. 

I really need to find someone to sharpen so we could better determine what we are doing. A friend of mine that used to run a circle and a band mill told me that he sharpened his new blades before using them. He cut grade lumber and sticks for several years.   I am trying to build a sharpener at the present . Hopefully I can get it done and experiment     


JP,  there is a lot to be learned.

[jpgreen]

Boy there certainly is Dick.

I've got to get the mill operating then learn how to use it, and I've got to build a table for my setter, and learn how to use my sharpener before I can really started sawing..  :D

But not as hard as what you're up against cause you still have to build your equipment.. 

I guess I should quit whining..  ;D