What causes blade to dive?

[ccb]

Blade started to dive with the fourth cut.  Cutting 21" red oak. The first 2-3" of the log, the blade dives, and then straightens out for the remaining 8' of log. Blade tension is good. Lubing new blade. Premium wood/no knots. What is causing this?

[godzilla]

I'm new to milling, been at it less than one year. With that said, I have had this happen when a blade starts to get dull, and I try to get just one more board out of it. I usually dull them with dirt I did not see(skid everything old school with tractors), and I go thru a tough spot such as knot, change in direction etc. I have read the explanation on here that as the blade dulls, it requires more force to get thru the cut and causes blade deflection. Just what i have read/experienced so far, hope that helps.

[tnaz]

Welcome to the forum CCB; wish I could help but I can't.  Looks like a new mill, throw a little more info up like year and size of mill and someone will be helping shortly.

Good luck,

Terry

[ccb]

2016 mill. LT50. New sawyer. Can't believe blade would be dull after 4 passes, even though this is select oak.

[tnaz]

From what I've read, new blade can be bad out of the box?  Did you try a new blade?

[Kbeitz]

If it happens when you first enter the cut then I would say its a speed change.
It take a sec. for the gov. to stabilize the RPM. So the engine speed drops
until the gov. kicks in to get the speed up to running RPM.
Try entering slower so you engine has time to catch up.

[derhntr]

Entry speed in the log can cause that to happen, mine will do that

[Magicman]

First, Welcome to the Forestry Forum, ccb.  That was easy, but tackling diving problems sometimes are not so easy.

The sawmill looks spanking new, Congrats.  How much have you sawn?  The first thing that I always look at is the blade:  (1) Blade sharpness.  (2) Is there any buildup on the blade?  (3) Change it to a new blade and see if the problem duplicates.  (4) Blade tension.  (5) Drive belt slipping causing the blade to slow down. 

After you eliminate the blade, you will need to took toward alignment.

And lastly, that log could cause you some grief because blades will sometimes try to take the path of least resistance.  With the fork, that log could cause strange things.

[Ox]

I'd say the fork/crotch of that log is causing you grief.  That's funny grain patterns right there and can make your blade wander some, even if everything else is perfect.  But I would also try a spankin' new blade as well.

[Dad2FourWI]

Hey ccb!!

It was a hot day but I enjoyed spending the day with you, the boss, and the mill !!   ;D

The blade did dive a bit on the 2nd to the last cut when I sped it up a bit as well... so I am still thinking it was the blade. It just feels odd that the blade could dull that quickly.... what, 4 cuts?? Yes, the log was a monster and that Red Oak was a dense as a rock... but at that rate I will take another three blades to get through the rest of the log!!!  :D :D :D

Always fun to spend the day making dust with a fellow FF member!!!  8)

-Dad2FourWI

[Magicman]

I wondered about that "other" person in the 3rd picture.   ;D

[Dad2FourWI]

Ohhhhhh...... that was my tummy!!!!!  >:(

I'm working on it.... but it is taking longer these days!!!  :D :D :D

It was a fun time.... but ccb became angry at me when he kept wiping up my drool marks on that nice new mill !

Is that what the Wood Mizer Orange is supposed to look like???? - mine looks more "salmon" colored........  :D

-Dad2FourWI

[Chuck White]

Welcome to the Forestry Forum, CCB and godzilla!

[Seaman]

Welcome to the maddness!
I would change blades first, change speed second, and turn the log around if neither work. Logs can be funny, and several have just whupped my butt !
Frank

[Seavee]

Welcome ccb. I have the same mill ,  a 2016 LT50 with a 47hp diesel. I had a simile problem at about 20 hours on the mill. It turned out the drive belt only had just under 10lbs of tension on it. I adjusted the belt and checked all the blade roller adjustments. The guide arm was just a hair loose also! All is good now. My suggestion is after the blade is ruled out check belt tension then go to the blade guide section in the manual

[Magicman]

The blade did dive a bit on the 2nd to the last cut when I sped it up a bit as well... so I am still thinking it was the blade. It just feels odd that the blade could dull that quickly....

Yup your description sounds like drive belt tension.  (See item 5 in Reply #7 above.)  A blade can dull in one cut if it hits hidden dirt, sand, or other unseen object(s).

It's just a process of elimination verifying and testing to find the diving cause.

[ccb]

The blade that was on had only made 4 passes, so I will put a new blade on.  The speed of entry was incredibly slow and at one point I shut the drive off and pushed it manually.  If I continue to have issues, I'll check belt tension.  Alignment seems to be good.  Thanks for your suggestions. 

To remove some of that unwanted bark around your midsection Dad2FourWI, you may need more mill time with your fellow FF member.  That may help stop some of the undesirable drooling  :D  :D   :D    We so appreciated your help! 

[Peter Drouin]

Welcome to the FF, Blade not level with the bed.

[Stuart Caruk]

You noted that the blade dives, but then cuts straight. I used to have the same issue. Lot's of things can make the blade dive, but rarely will it go straight again after that. I found my issues to be from lack of blade lube. Pitch would build up on the blade, sawdust can't get out freely and the blade binds up. It has to go somewhere so it would dive then straighten out  as the pitch cleaned off. I went back to using blade lube and the problems went away.

Now I usually saw dry, but if I see gunk starting to stick to the blade I turn on the lube to clean it. If it's a critical cut (last one to finish a beam) I'll just run the lube as a precaution.

Every time I stopped after the blade dove, the blade was covered in pitch. Coincidence.... I think not.

[ccb]

Made it through that big log with no problems after changing the blade again, other than hitting a nail in the second to last cut.  Did one more large log with another new blade and only issue was going through a knot.  Once slowing down with the next cut through the knot, no issues.  Big shout out to Dad2FourWI for letting us borrow the edger - THANK YOU!  A definite "must have."  Still feeling exhausted after milling for two days in this heat & humidity.  Wanted to post some new pics here of today's large logs, but can't seem to make that happen.

[drobertson]

Some good input so far, just wondering if you got through the log and started another?  One mentioned blade speed, so if this is your first log then maybe so. Another mentioned drive belt tension, good place to look, but this usually shows up for the length of the log.  There are many variables, and not knowing every condition, its very hard to nail down.  SOG can cause issues, seen it many times, very frustrating.  Please keep us posted on your conclusion.

[ccb]

My final conclusion is that it was the blade, since that corrected everything. And, I had no issues with the next log I cut. Thank you everyone for your input.

[drobertson]

Wife got me this tablet just starting to learn it, glad you got it! Never saw your last post! Ha ha

[Dad2FourWI]

Hey ccb!

Glad to be able to help out another FF member! - trying to repay all the kindness that these members have sent my way!!!  ;D

I would tell you to buy more blades.... but I think you are all set there!

That edger is sweet, albeit a bit small... but it works for me... 99% of the boards that I cut are 12" and less!!! - I wish I could say otherwise! !!!

I picked up the edger today.... WOW!.... you did not have to clean and wax it!!! ... and I don't think I will have to add gas for a month!  :D :D

I think you and the boss should come visit on your week off...... ???

Take care and stay cool!
-Dad2FourWI