I was sawing a white oak today that was about 18 inches on the small end and 25 inches on the big end. I started out with a brand new 7 degree blade. On the second cut I noticed the blade dove significantly about half way through the cut and the blade tension backed off by about 500lbs.
I made another cut and slowed way down and the blade started out good but by the time I had cut to the other end of the log (I was sawing from the small end to the big end) the blade was starting to "dish out" in the middle.
I kept the blade at the same height and backed up back over the log. You can see how in the first picture that the blade rests evenly on the log where I began the cut (little end)
(https://forestryforum.com/gallery/albums/userpics/39073/20160220_110353.jpg)
In this picture there is 1/2 inch difference between the blade and the log (big end of the log on the same cut). Its hard to tell in the picture but there is more space between the log and blade in the middle than on the edges.
(https://forestryforum.com/gallery/albums/userpics/39073/20160220_110502.jpg)
This is not the first time I have noticed this cutting hardwood. I have checked my blade guides and blade for alignment problems, and everything seems to be OK.
Changed to a 4 degree blade and it cut better, but not perfectly. Still wanted to "dish out" in the middle of the wide cuts.
Are you loosing RPM's ?
what set are you running,
drop in band tension would be from heat??
Dan
I would suggest 3 places to start...first suspect is a blade issue, not enough set, not sharp enough...I know you've tried a few, but runs on new bad/poor blades is not unheard of...2nd, loss of tension indicates the potential support of the first, as the blades performance is sub par, it is accumulating heat as a result of this, causing the drop in tension...or a tensioner problem. Third, slipping drive belt...didn't make sense when I first thought about it, but a slipping belt could initially cause a dive or variation, and the blade could be creating heat as it struggles to get back where it should be...
Yep check set. just because a blade is new doesn't mean its set right. I had a box once that wasn't set on one side.
Maybe you're moving the blade through the log too fast.
I'm not sure what HP your engine is.
When we say. "try slowing your cut down"......I'm not sure a lot of sawyers no what we mean.
I run a 29 hp which in reality is a 26.
I have seen some White Oaks that have S L O W L Y grown over the years and are tough as nails.
I have sawn a few tough 'Ol WO" logs in the past.
Even with a brand new 4° blade, I have to slow down to get a smooth cut.
I'm talking about creeping slow and pour the lube to the blade.
Again, some of these White Oaks are tough old birds. ;D
Quote from: Kbeitz on February 20, 2016, 05:45:55 PM
Are you loosing RPM's ?
I run a 36HP yanmar diesel and can hear the engine bog down when you really push it. If I hear it bog down I slow down my feed rate to try keep my RPMs at their peak. I cut some 12 inch poplar siding today and some 20+ inch wide live edge cedar boards (knots all over the place) with the same 4 degree blade that I cut that big oak with and it performed flawlessly.
Quote from: bkaimwood on February 20, 2016, 06:40:19 PM
I would suggest 3 places to start...first suspect is a blade issue, not enough set, not sharp enough...I know you've tried a few, but runs on new bad/poor blades is not unheard of...2nd, loss of tension indicates the potential support of the first, as the blades performance is sub par, it is accumulating heat as a result of this, causing the drop in tension...or a tensioner problem. Third, slipping drive belt...didn't make sense when I first thought about it, but a slipping belt could initially cause a dive or variation, and the blade could be creating heat as it struggles to get back where it should be...
I would agree that when I saw the tension drop my blade was definitely getting hot and stretching. It is possible that my drive belt is not tight enough. I did adjust it about 40 hours ago at the 50 hour first service interval. I will double check that tomorrow.
Quote from: POSTONLT40HD on February 20, 2016, 08:32:18 PM
I'm not sure what HP your engine is.
When we say. "try slowing your cut down"......I'm not sure a lot of sawyers no what we mean.
I run a 29 hp which in reality is a 26.
I have seen some White Oaks that have S L O W L Y grown over the years and are tough as nails.
I have sawn a few tough 'Ol WO" logs in the past.
Even with a brand new 4° blade, I have to slow down to get a smooth cut.
I'm talking about creeping slow and pour the lube to the blade.
Again, some of these White Oaks are tough old birds. ;D
I have not ruled out my feed rate either. I just got this mill back in March of 2015. Before that I was running an LT40 manual with a 18HP briggs. I cut some pretty big (36+ inch) white oaks and you would just barely crawl through them.
This new mill with the diesel has so much more power that it is really easy to exceed the limitations of the blade because the engine will handle it.
Cutting softer woods like clear pine or poplar you can really push your feed rate up, even on wide logs and not have any problems.
I wish I would have turned that log around today and started on the butt end to see if that would have made a difference.
The diesel will certainly pull that blade quite well.
What thickness are the bands are you running.
Dan
The only problem I see with slowing the feed rate down, is that the blade spends more time in the cut, which actually causes more heat, more blade tension loss, and worsens the problem... Flooding the blade with water may help, but I've found when I have to do this, I'm only masking a blade problem. Something that may help us diagnose this...what kind of dust are you getting? Fine? Normal? Chunky? Floury about the blade and cant?
Quote from: dgdrls on February 20, 2016, 09:39:38 PM
The diesel will certainly pull that blade quite well.
What thickness are the bands are you running.
Dan
The 7 degree blade that preformed so poorly is 0.045 and my 4 degree blades are 0.055 thick and I am really impressed with their performance in terms of amount of lumber that they can cut before showing signs of dullness.
Quote from: bkaimwood on February 20, 2016, 09:53:01 PM
The only problem I see with slowing the feed rate down, is that the blade spends more time in the cut, which actually causes more heat, more blade tension loss, and worsens the problem... Flooding the blade with water may help, but I've found when I have to do this, I'm only masking a blade problem. Something that may help us diagnose this...what kind of dust are you getting? Fine? Normal? Chunky? Floury about the blade and cant?
When cutting that white oak today, there was a lot of sawdust stuck to the boards I was cutting. I was quarter sawing and after every cut there would be a layer of dust caked on each board. I would have to deliberately rake the sawdust off after each cut to look at grain on each board. I was running a good bit of water on the blade.
Quote from: ncsawyer on February 20, 2016, 10:21:50 PM
When cutting that white oak today, there was a lot of sawdust stuck to the boards I was cutting. I was quarter sawing and after every cut there would be a layer of dust caked on each board. I would have to deliberately rake the sawdust off after each cut to look at grain on each board. I was running a good bit of water on the blade.
This will happen. :)
Quote from: POSTONLT40HD on February 20, 2016, 10:57:40 PM
Quote from: ncsawyer on February 20, 2016, 10:21:50 PM
When cutting that white oak today, there was a lot of sawdust stuck to the boards I was cutting. I was quarter sawing and after every cut there would be a layer of dust caked on each board. I would have to deliberately rake the sawdust off after each cut to look at grain on each board. I was running a good bit of water on the blade.
This will happen. :)
I agree, and with running extra lube, it can make it worse...I am learning to read the dust, but so far have determined that finer than normal dust is an indicator of blade troubles....fine flour, especially riding on top is the sure fire indicator of blade troubles, right next to burn marks :D. I know there are fellas here that are much more experienced in this and was hoping we could improve the symptom list to aid in diagnosis...
It could be the blade, and it could be your drive belt too, hard to call from this end, I will say I have had very similar results in large somewhat large knots too in WO, I changed the new blade and all went away. When you talk about bogging the engine, I wonder how much bog? Pushing too much can make waves too, hope you get it figured out,
Quote from: bkaimwood on February 21, 2016, 08:36:33 AM
Quote from: POSTONLT40HD on February 20, 2016, 10:57:40 PM
Quote from: ncsawyer on February 20, 2016, 10:21:50 PM
When cutting that white oak today, there was a lot of sawdust stuck to the boards I was cutting. I was quarter sawing and after every cut there would be a layer of dust caked on each board. I would have to deliberately rake the sawdust off after each cut to look at grain on each board. I was running a good bit of water on the blade.
This will happen. :)
I agree, and with running extra lube, it can make it worse...I am learning to read the dust, but so far have determined that finer than normal dust is an indicator of blade troubles....fine flour, especially riding on top is the sure fire indicator of blade troubles, right next to burn marks :D. I know there are fellas here that are much more experienced in this and was hoping we could improve the symptom list to aid in diagnosis...
Adding to the list of facts
1-1/4" or 1-1/2" bands???
are the sawn boards or the cant leaving tooth marks?
bkaimwood is right on, the sawdust is the messenger.
Dan
i have the same problems sawing w/o especially if they have been cut for a while more than likely if you had turned the log around and sawed from other end it would have had a hump instead of a dip at least thats what the ones i turn around did its no better just different. i just try not to saw w/o unless the logs are really fresh ;D most of the time i can saw w/o fairly flat but it is harder to saw than most species after it lays there and dries a while i would just as soon saw hickory or pecan >:(
:new_year:
Quote from: dgdrls on February 21, 2016, 09:53:00 AM
Adding to the list of facts
1-1/4" or 1-1/2" bands???
are the sawn boards or the cant leaving tooth marks?
bkaimwood is right on, the sawdust is the messenger.
Dan
I run 1.25 inch blades. Didn't really see any saw marks. The blade left a very smooth finish on both the log and boards.
I cut WO and all kinds of wood in NH, And when The cut is not flat the blade is dull. The only time I use lube is on dry older W Pine for the pitch, Somes times with ash for one cut, and not unless the pitch is on the blade again, Lube one more time. But by that time i'm on another log.
I cut dry all the time.
I just got through the exact same problem. especially in hardwood for no reason my blade would dive. I tried slowing down I always change the bands when It did this. But I had no idea why therefore no idea how to fix the problem until I went to get my band sharpened. I send them out to get them sharpened and the fellow told me that the set was off one side not the other. He told me to make sure my band was level to the bed. Not horizontally. From the back of the band to the front of the band level with the bed within 10,000s of an inch. He lent me a tool made by wood miser for checking this when I checked and sure enough it was out by significant amount. Took me a month to figure it out. After 10 years of service my support arms were twisted a little from blade tensioning. And more importantly my guide rollers were different from the front of the roller to the back by three 10,000s of an inch throwing the whole system out. I ordered new guide rollers problem fixed.
Good luck
Quote from: Peter Drouin on February 21, 2016, 07:11:37 PM
I cut WO and all kinds of wood in NH, And when The cut is not flat the blade is dull. The only time I use lube is on dry older W Pine for the pitch, Somes times with ash for one cut, and not unless the pitch is on the blade again, Lube one more time. But by that time i'm on another log.
I cut dry all the time.
Peter, I am gonna call you out on this one, if you don't get wave with sharp blades, then I would sure like to know the recipe, I know you are hogging it, so My guess is you have looser tolerances? and you don't slow down? there's no way to saw at speed with some logs, and I could not care less what folks say,,, flat is flat, period, I like to be a hero like most folks but the fact is the nature of the beast, which is bastard logs, that try us,,,
On big WO I've put on a brand new 10° blade that dove bad in the first 3' and then sharpened the same blade to 4° and it cut perfect just under the first cut, after that happened at least 3 times I use 4° for everything. My supplier only sells 10° so I use them the first time in easy to cut wood. Steve
Quote from: drobertson on February 21, 2016, 08:12:16 PM
Quote from: Peter Drouin on February 21, 2016, 07:11:37 PM
I cut WO and all kinds of wood in NH, And when The cut is not flat the blade is dull. The only time I use lube is on dry older W Pine for the pitch, Somes times with ash for one cut, and not unless the pitch is on the blade again, Lube one more time. But by that time i'm on another log.
I cut dry all the time.
Peter, I am gonna call you out on this one, if you don't get wave with sharp blades, then I would sure like to know the recipe, I know you are hogging it, so My guess is you have looser tolerances? and you don't slow down? there's no way to saw at speed with some logs, and I could not care less what folks say,,, flat is flat, period, I like to be a hero like most folks but the fact is the nature of the beast, which is bastard logs, that try us,,,
:D :D :D
When I put on a new blade 1¼x55x7° sometimes it will wave. The set is off or is dull. After I push out the set to 30 from 22 to 25 WM sets at and sharpen to a flat top tooth. [WM sharpens then sets] and that will have the top of the tooth off square.
Some logs will give you some trouble, and yes, I have to slow some on logs like that. But, what I find is going to slow will give you more trouble. It gives the blade time to wander and dull. Every log has a sweet spot, and I look for that. I have a speed button just like you do. When I put on a log I can tell if I have a trouble maker or not. You have the same mill as me but, I have a chair and can run my hand on the ride back from the cut . And your hand will feel the wave long before your eyes will see it.
Cutting frozen hemlock with a 4" knot will test you. :D :D
That's why I'm heat treating blades now, After one log the blade tooth is rounder over when I sharping past the hard part. With the heat treat I can cut 3 to 4 logs.
I don't like to spend all my time changing blades. ;D
The new CBM and setter makes It easy on me to keep a good blade on the mill.
Looser tolerances. :D :D :D really, I just have to be smarter than the log.
How do you say it, lumber is spot on. You saw long enough, you will get it. ;D
Good luck.
Quote from: drobertson on February 21, 2016, 08:12:16 PM
the fact is the nature of the beast, which is bastard logs, that try us,,,
i had a 28" red gum last fall that i could not cut a slab off of last summer i could saw down to about 6' on the 8' log and it would kill the engine no matter how slow. i was sawing from butt end and turn the log around and it sawed with no trouble except the slabs curled up a full 6" by the time i got to the far end :o the boards did that all the way down to the cant even the 7x9 ties had about 3" of sweep to them but i did split the pith both ways and made 4 ties :o just to get the thing off the mill. also had a few pine that would be so wavy that it was useless and turned log around and sawed out fine ??? after you have sawed awhile you know it the blade is dull or if something else is causing the problems the dust will tell you alot more about blade sharpness than the cut imo :) and i do agree with peter about you can go to slow :)
popcorn_smiley
The first thing I need to say is a diving blade just stinks, so, try and figure why it's diving. Hard, dry, and wide white oak is a good reason for bad blade behavior, as to Peter's response, I feel a rebuttal is due, not for arguments sake but clarification, in post # 17 of this thread pete said diving is a dull blade,, in post 21 he said the set on wmz's could be off, so he would change them, which leads me to believe that all of us struggle at times with tough logs. And to add I did not,,Not mean Peter sawed crap lumber, I simply meant that some requirements allow for faster feeds and looser tolerances, not that Peter cant' saw flat,, anyone with a wmz, aligned properly, good blades and some know how can produce flat stock, providing the log behaves,, and yes,, hopefully one day I will get it figured out,, ps,, feeds have to be learned with the available horse power of a given machine,and the proper cutting tools,,
Sometimes when I put on a new WM blade [ all I use] on the first cut I can see it's off. So it goes on the dull pile. :D :D Only one cut and I have to set and sharpen it.
So when I sharpen all the blades, they all get set at 30 is all. That is what works for me.
I did find if you cut crane mats, You can let the tolerances go some. :D :D :D :D
That's all I was saying brother, a good thing I have found, not diss to any other maker,,, but the Kasco's are spot on, you ought to give them a go,, at least a go, can't hurt, and the resharpen really good too,, very little breakage,
Peter I sure appreciate you man, you are a go for it kind of guy,, just today a fellow called and asked about some sawing,,, I said you bet,, he said,,"Man, you ain't afraid of nothing are you'" I said well I am losing hair, but beats the heck out of standing on concrete all day,, he said, see you in a few days,,, old customer,,
smiley_thumbsup