Blue-blade society wows and frustrations

[GDinMaine]

I finally got to saw some oak and I now understand why people love that stuff.  My love affair lasted all the way through the first log as I was proudly looking at the nice boards and the blueish tint on the blade. (Hence blue-blade society). Things turned sour in the second log.

Due to bad judgement I managed to get the blade jump off the wheels just after I sawed three faces on the second log.  No problem.  I know I made a mistake and just put a freshly resharpened 7s blade on there. That second blade made it about 14" into the cut diving like crazy.  It was 1/2-3/4 before I realized.  I got that out of the log without damage.

After talking with another sawyer I followed his suggestion and put a brand new 9s blade on the mill.  It sawed diving after 3ft into the cut.  Second phone call.  He said to check the roller alignment to be sure it's spot on to eliminate that as a problem. He also said that it is a possibility that the log is the trouble not my saw.

My outside roller is pointing down by about 1/16"-3/32" measured on the alignment tool. At that point I ran out of time and had to go to my day job. Will go back to deal with this tomorrow.

It is red oak that has only been down a month or so.  I used water and then I shut it off to see if that makes a difference.  I slowed down but didn't go very slow.  The drive belt tension was adjusted just about 100+- hours ago by WM tech.
I sawed the trouble log from the small end.  Should I turn it around?   
I will start with adjusting roller that slightly off and might try to saw another log, to see if the blade tracks properly. 

Sawing oak seems very rewarding, but I'm frustrated at the moment. 
I wonder if I can get some pointers on what I might be doing wrong.
The mill is a WM LT40hd with a 42hp diesel.
Thanks

[Dave Shepard]

WM says to check drive belt every 50. In hard sawing, I'd do it more often.

[POSTON WIDEHEAD]

Was there a knot somewhere where the blade was diving?
In Red Oak, a brand new blade will dive if your head speed is a little fast.
Were you sawing WIDE boards?

[ladylake]

red oak saws easy with almost any blade, I'd check everything including down pressure.  Steve

[Nomad]

     If you jumped the blade you may well have thrown something out of whack.  Do an alignment check on the head.  And fix the problem you've already found!

[GDinMaine]

Was there a knot somewhere where the blade was diving?
In Red Oak, a brand new blade will dive if your head speed is a little fast.
Were you sawing WIDE boards?

There was no knot it just took off downward and kept on going. Not just a dip and then come back up.

Are you pulling my leg with that statement about new blades?  If not, then I learned something very surprising today.  The boards were around 8-15" wide as I was cutting off the butt flare.  Interestingly the blade I jumped was midway through it's sharp life and was cutting fine. The other two I tried were a freshly resharpened 7 and and brand new 9.  I forgot to mention, that I was trying to back 3" out of the last face I opened too deep. Thought I can produce an extra 5" or 6" wide short board and I got myself into this fix.
Will check alignment in the morning and get one of my own logs on the mill to test things out.

Thank you all for the pointers.

[YellowHammer]

I use the basic characteristic of the blade dive to help troubleshoot the problem, and narrow down the cause.  These are just observations and opinions I use, others my disagree.

A properly adjusted and aligned mill will try to self correct.  If the blade is cutting a wave, a rise or fall where the blade keeps passing through the neutral centerline of the cut, it indicates that the fundamental mechanical sawing system is fine, and is actually trying to self correct itself  i.e. pull the blade back to centerline but for some reason it can't hold, so creates a wave.  The issue is most likely anything but the mill itself, and may the log (knots), sawing technique, feed speed, blade tension, wrong blade for the log, etc.  Even a temporary blade dive with a loose drive belt will quickly self correct to neutral indicating the mill is aligned properly.

If the blade dive or rise is only in one direction, constant up or down, with no return to neutral, then the mill is not trying to self correct, and signifies a fundamental mechanical issue with the blade or the mill.  I would fix the blade alignment (I like to get within 1/32 inch) and if that doesn't fix it, start looking for things that may have been caused by the thrown blade. Did the band wheel belts get chewed by the thrown blade?  Are the teeth touching the band wheels so removing set?  Check the new but misbehaving bands-are they still sharp or are they dulled from contacting something?  Recheck to see if you have a loose guide arm, adequate down pressure, things like that. 

I hope this helps
YH

[Alyeska Pete]

Check the tension.

[JohnM]

I stopped in at GD's yesterday just as he was packing up the mill.  Stopped thinking the mill was on fire, turns out it was just steam venting from his ears. ;D ;)  I have no doubt it'll be up to snuff shortly.

[GDinMaine]

I ended up checking the alignment and it was not as far off as I previously thought.  I made the very small adjustments anyway, but the blade kept diving.  A fellow sawyer/friend ended up coming over to look at the logs and the mill.  He said it was the log due to way off center pith, growth ring pattern and tension.  I could not believe it.  He said: "Saw that one!" pointing at the next one in line.  I took the misbehaving cant off the mill and sawed up the next log without any trouble.  I guess the man knows what he is talking about after 12,000+ hours behind the control of a mill.  I ended up doing a fair bit of checking and maintenance on the mill.  I consider that time well spent.   Thanks all who made suggestions.

[barbender]

That's what you get for not giving us pictures ;D I'm glad you got it figured out.

[beenthere]

Do you have pics of that log that gave you trouble, to show others what they should look out for when sawing?

[Magicman]

You sawed one log OK, and then opened three faces on the second log OK.  Next your blade starts to dive ~14" into the 4th face.  I would tend to suspect that there might be metal inside of the 4th face.  Just a thought.

[Brucer]

...  If the blade is cutting a wave, a rise or fall where the blade keeps passing through the neutral centerline of the cut, it indicates that the fundamental mechanical sawing system is fine, and is actually trying to self correct itself  i.e. pull the blade back to centerline but for some reason it can't hold, so creates a wave.  The issue is most likely anything but the mill itself, and may the log (knots), sawing technique, feed speed, blade tension, wrong blade for the log, etc. ...

Not necessarily.

If the blade guide rollers aren't properly aligned in the horizontal plane, the flange can pull the back of the blade down, causing the blade to start to climb. As the tension in the blade increases, the blade will snap back to its proper position and start to drop back down to it's proper depth. Then the cycle repeats, causing waves in the wood.

A sloppy blade guide roller bearing will have a similar effect.

[5quarter]

This doesn't add up. I've had blades dive on me when sawing oak, but the cause has always been either lack of power or loss of set to the inside teeth. Power is obviously not you're problem and your belt tension is good, something knocked the set out; blade guides, bandwheel rims, tramp metal in the log...something. Did you change blades when putting on the log your sawyer friend said or was it the same blade that dove in the previous cut? If it was the same blade, then its a real puzzle.
I do recall that I had a diving issue when sawing a massive Bur Oak crotch. I was maxxed out at 26" and the blade started diving and crowning on the second cut. I pulled the blade and put on a fresh one and got the same problem to a lesser extent when I tried to clean up the mess I made of the second cut. I pulled the blade and examined the teeth under 5x magnification. brand new out of the box, the outer edges of many of the teeth were not completely square. I resharpened the blade until the edges were square and the edges were like razors. that solved my diving problem...cuts dead on straight. In addition to sawing through the crotch, I was also cutting through highly figured compression wood on both sides of the crotch. Perhaps you were sawing compression wood on that last face. if so, you might put the problem child  back on and put your 3rd face up and saw it to the deck. I too would like to see a couple pics of the trouble you were having.
Also, Your movable roller guide should always run as close to the log/cant as possible. as the guide arm is pulled out, you loose beam strength, which makes it easier for your blade to wander, especially if things are not dialed in just right.
I'll hang up now and listen to the panels comments.  ;)

[GDinMaine]

To this strange story there is even a more strange ending.  As I said I did a slight adjustment to the outside blade guide roller and that was the only change on the mill.  After sawing two other logs without major trouble I decided to put the suspect cant back on the mill.  Mind you I have changed nothing, not even the blade.  To my absolute shock I was able to saw the cant without issues.  I mean really!!! What the sausage?  The only thing that was different that I sawwed two relatively dirty dry oak logs.  This makes me think that POSTON LT40 was not kidding about new blades sometimes  diving in oak.  Granted all but two of the logs produced some significantly stressed lumber even tho I flipped the cants after each cut or two at the most.  I feel like I learned something but I'm not quite sure what.  I did take pictures of the off center piths and ill post them whe I have time to upload.
Thanks for all the advice.  I will have to re-read all of it and try to remember.

[beenthere]

As I said I did a slight adjustment to the outside blade guide roller and that was the only change on the mill.

And you don't think this is what made the difference?

[Nomad]

     I'm with Beenthere.  What seems like a slight adjustment to you didn't seem so slight to your mill.  (The steering doesn't pull anymore?  They only made a little adjustment.) ;D  Glad you got it straightened out.

[Magicman]

I ended up checking the alignment and it was not as far off as I previously thought.  I made the very small adjustments anyway, but the blade kept diving.

???   ???  Yes, very confusing.   

[GDinMaine]

It sure is confusing the daylights out of me.  It could have been the slight adjustment but I had some trouble after that.

When I have a problem with a machine it is usually resolved by diagnosis of problem followed by adjustment or repair.  In this case I have no idea what particular action contributed directly to the resolution.  It just made me a bit afraid of sawing this kind of stuff.

[LeeB]

Is it possible that you had a piece of bark or some such stuck somewhere that was deflecting the blade down and finally dislodged it after a couple of blade changes?

[YellowHammer]

It just made me a bit afraid of sawing this kind of stuff.

I have about the same mill and engine combination as you, and know that this (your) saw configuration will rip through red oak.  The log should be afraid of you.  :D

YH

[PC-Urban-Sawyer]

...  It just made me a bit afraid of sawing this kind of stuff.

Remember, as FDR said, "All we have to fear is fear itself..."

And as the Bible says in several places: "Be not afraid..."

Herb

[GDinMaine]

double post oops

[GDinMaine]

Here are the images of the logs that gave me the most trouble.  The arrow marks the pith.

This is the butt log that is roughly 13"x11" cant in this picture.



 

Here is the second log from the same tree.  It sawed up better but there was a good fair bit of tension in the log.