Blade Problems on Doug Fir

[highleadtimber16]

Hi Guys, Been reading stuff on the forum for over a year now and thought I would join in.
Today I thought I would take a break from the cedar and tackle a couple of fir logs. I had an order for 3X8's and 6X12's. While cutting my first 6X12 my blade dove down almost on inch near the end of the cut, most likely due to the pitch. I then filled up my water tank with soap, antifreeze, and water. No luck. Do guys have any tricks or solutions for these problems? I thought about using diesel on the blade but don't really want to. These aren't my logs so I don't want to mess them up to bad.

[dgdrls]

Have you tried Pinesol in the Lube tank??

A cupfull or so with hot water should help the pitch buildup.

I have seen posts where folks run bristle brush on the band

Other's use liquid auto- dishwasher soap, Cascade perhaps?

DGdrls

[John Bartley]

In winter I use WW fluid.

10L of WW with 10TBSP of Pinesol and 10TBSP of water soluble machining oil.  I rarely have any sort of buildup of pitch. In summer I use plain water as the base, with the same Pinesol and Machining oil.

John

[Magicman]

Hello, highleadtimber16 and Welcome to the Forestry Forum.

Of course I have never sawed DF, but I would think that you should already be using 100% -32° WW fluid to prevent freezing.  To that I would add about 2 oz. of liquid Cascade per gallon.  I would adjust for a constant trickle.  Lube is cheap.

Your blade dive could have been caused by pitch build up, but there is also a possibility that the blade may have hit an unseen rock, etc.

[drobertson]

welcome highlead, I have not cut df, so I thought about not even posting, but this said I have had the same issues with syp, if all is well until the end of the cut I am assuming it is a butt end.  The pitch can be bad on syp as well. I have changed blades to fix the problem, and might mention checking you drive belt tension as well. at that point in the log it might take just a bit more power transmission to keep the blade on steady cut.  I witnessed two days ago a good freind who switched to diesel with great results, no staining on the lumber. Oak not df or syp, but just the same no staining. Belt tension, drive belt tension, sharp bands and good alignment are critical. Anyone of these issues can make one scratch their head. david :christmas:

[Magicman]

Thanks David.  I forgot to ask if the log butt was on the entrance or exit end.   :P

[captain_crunch]

What cut of tree was it?? Butt cuts dont happen on my mill first 8 ft is fire  wood Timberbind is an ugly thing to deal with

[highleadtimber16]

Hey, Thanks for the tips. The butt was on the exit of the cut. I really should check my belt tension and will do that tomorrow. Alignment is good and blades were brand new so belts are probably playing a key role in this issue. I may try a little bit of diesel also. This is why I prefer cutting cedar. Thanks!  :christmas:

[drobertson]

I use to really dislike butt ends, I mean I would make fire wood real quick, but when buying logs already bucked to length, there is no choice in the matter.  I have found, not scientifically, but blade sharpness and drive belt tension are the culprits.  I think the resign or pitch requires more hp. And this problem for me only happens on cuts that in the 20"+ wide butts. After the initial flare has been removed and the width goes down the problem goes away for me, providing the blade is clean and sharp.  I don't have the drive belt tension tool, so I am careful not to over tighten it.

[Magicman]

It was almost a given that you hit the tension that was in the butt of the log.  I call it "compression" because the weight of the tree sorta buckles the bark.  That butt end has worked hard all of it's life and you will have to pay for sawing it.   :-\

[losttheplot]

I keep a small hand crank oil can on the mill, it contains 50/50 chainsaw bar oil and diesel.
I give the band a squirt on each side as it is spinning flat out.
It cleans the sap off in seconds.

I do this at the end of the cut if there is sap build up, keep the blade spinning all the way back for the next cut and there won't be much diesel left on the band.
I also give the band a squirt on each side before I take it off for sharpening, it's easier than cleaning the band manually and stops it from getting surface rust if it's sitting for a while.

I have seen no sign of the diesel on the cut wood, there are no rainbows on the fresh sawn wood  when it is raining.
I like the diesel/chain lube so much I am going to put a wick system on my mill just as soon as I finish my honey-do list  ;D

The only time I have had a band dive/rise in Douglas-fir it has been from pushing too hard and slowing the band speed.

Hope you enjoyed the sunshine today   

[redbeard]

Cedar will do the dive at the end also especially with the sap build up and compression wood in the butt ends. I also have been using diesel n used hydraulic oil mix using a spray bottle and iam having excellent results removing the pitch. If this is happening consistently the guide rollers might not be plumb and could be only one of them is off a little. The blade is really working at the end of cut  especially if log is getting wider at the end.  I had that problem a few weeks ago but it was diving up so slabs mostly were slamming into guide roller and actually bent the bearing bolt just enough to knock out of plumb. Doug Fir costs more to mill in the long run compared to cedar on band blade exspence. The really straight ones with a bulls eye pith dead center cut the best and produce the best obviously. Its when your trying to get lumber from logs with sweep, butt swell and big knots. Things slow down and cause obstacle milling. Sometimes there's better money selling those for firewood.

[highleadtimber16]

Usually I would just cut the butt logs up for firewood or even most fir for that matter, but they weren't my logs. I very rarely have any problems with cedar, it is old strait charlotte wood so it's very easy to deal with.

[ladylake]

 Diesel works good, just a drop every second or 2.    Steve

[haywire woodlot]

Welcome aboard Highlead! Where are you getting your logs from? I used to dump log barges from up north in Stillwater Bay down the road from you.
All good advice here and cedar can be tricky for diving cuts too.

[highleadtimber16]

Welcome aboard Highlead! Where are you getting your logs from? I used to dump log barges from up north in Stillwater Bay down the road from you.
All good advice here and cedar can be tricky for diving cuts too.

I get my logs from Husby. They come down by the barge load, then dump them in howe sound at the twin creeks sort. It's about $165/cubic meter.

[Brucer]

I've sawn over 400,000 BF of Douglas-Fir and I rarely have a problem with the blade diving (unless there's a problem with the blade or the alignment).

One situation where the blade can dive suddenly is when you are sawing toward the butt of a log that has a significant flair or sweep (or both) at the end. That will often suck the blade down in the centre near the end of the log. It's more likely to happen on large diameters logs. The problem is worst when I'm sawing through the outside of the log -- as soon as the cant is squared up the problem diminishes or even disappears.

You can also have a blade dive if the sapwood is frozen. I've had the same thing happen on WRC. Once you get most of your cut below the sapwood the problem disappears.

An large pitch pockets in any species can cause a blade to pull down. The pitch coats the blade on both sides but the inside of the blade picks up sawdust as well and this gets pressed into the pitch as the blade goes around the bandwheels. The pitch on the outside doesn't pick up much sawdust and in any case it will get scraped of as the blade re-enters the log. The effect is similar to taking the set off the inside teeth, which will cause the blade to dive. When I hit pitch I open my blade lube valve all the way. At the end of the cut, if pitch is building up on the blade, I will leave the blade running with the coolant flooding the blade. But mainly I pay a premium for logs that don't have pitch pockets.

[ladylake]

I've sawn over 400,000 BF of Douglas-Fir and I rarely have a problem with the blade diving (unless there's a problem with the blade or the alignment).

One situation where the blade can dive suddenly is when you are sawing toward the butt of a log that has a significant flair or sweep (or both) at the end. That will often suck the blade down in the centre near the end of the log. It's more likely to happen on large diameters logs. The problem is worst when I'm sawing through the outside of the log -- as soon as the cant is squared up the problem diminishes or even disappears.

You can also have a blade dive if the sapwood is frozen. I've had the same thing happen on WRC. Once you get most of your cut below the sapwood the problem disappears.

An large pitch pockets in any species can cause a blade to pull down. The pitch coats the blade on both sides but the inside of the blade picks up sawdust as well and this gets pressed into the pitch as the blade goes around the bandwheels. The pitch on the outside doesn't pick up much sawdust and in any case it will get scraped of as the blade re-enters the log. The effect is similar to taking the set off the inside teeth, which will cause the blade to dive. When I hit pitch I open my blade lube valve all the way. At the end of the cut, if pitch is building up on the blade, I will leave the blade running with the coolant flooding the blade. But mainly I pay a premium for logs that don't have pitch pockets.

What hook angle are you running, I find 10* like to dip in the center, 4* will leave a hump when dull.  7* might be the best for those wide cuts.    Steve

[coastlogger]

Pour the diesel to er.My highly sophisticated D Fir lube system is a spray bottle of diesel in my right hand. As soon as I see a white line forming behind the teeth,thatll be pitch,I start flooding the blade with diesel and slow the feed to a crawl till the pitch line disappears.I generally get straight cuts although the slabbing cuts are not always as good,like Brucer says.
On my intend to do list is a lube system like Frank C's

[learner]

I only mention this because we found the problem a couple days ago.  Have you checked your blade guides?  On a woodmizer they should be .080-.010" from the bottom of the blade.  After we adjusted ours the blade flows smoothly even at full throat opening.  Before that our blade was fluttering as much as 1/2" on the entry and exit cuts.

[Brucer]

What hook angle are you running, I find 10* like to dip in the center, 4* will leave a hump when dull.  7* might be the best for those wide cuts.    Steve

I use WM 1-1/2" x 0.045 x 10 degree blades for nearly everything I saw. I have a few 7 degree blades that I used when resawing very dry, wide cuts for one customer. I never thought of using them in DF butt cuts: I'll try that next season and see how it works. Thanks for the tip, Steve.

[giant splinter]

I saw Douglas fir and Red fir more then anything else and have had only seen the blade dive a couple times at the end of the cut. I one case the cant was stressed and actually lifting itself off the bunks about a 16/inch, I could feel the mill working harder and gave my lube valve a twist further open while slowing the travel speed (this all happened in the last couple feet of the pass) after a close look I could see the unsatisfactory results, it was evident the blade was not in a position to be moved back for the next pass as it was slightly below the exit cut and off the end of the cant. I suspected the cant had raised just enough to cause this and turned the cant 180 degrees before setting up the next cut, checked the blade tension  before continuing and it went good after that.
In the other case the log was frozen and the mill was not happy as it was working harder to cut 8"X14" beams from the cant even with a new 4 deg. 1 1/2" blade and the cant well situated and not moving at all the blade dropped just enough to leave the end of the cut a hair out of thickness.
In both situations I was sawing beams that where 4"X10" and 8"x14" -  20'-0" in length.
There are many situations that would contribute to blade deflection and straying off course and a great deal of the sawyers on this forum have had at least a few times when this problem turned up, as always some expert advice has been shared by many of them to help us all get things working and running smoothly.

[Nerijus]

Hi Guys, Been reading stuff on the forum for over a year now and thought I would join in.
Today I thought I would take a break from the cedar and tackle a couple of fir logs. I had an order for 3X8's and 6X12's. While cutting my first 6X12 my blade dove down almost on inch near the end of the cut, most likely due to the pitch. I then filled up my water tank with soap, antifreeze, and water. No luck. Do guys have any tricks or solutions for these problems? I thought about using diesel on the blade but don't really want to. These aren't my logs so I don't want to mess them up to bad.

In ours, the main lumber is pine or fir, so I'm sawing it almost every day. In my experience, fir is not whimsical for lubrication, samil setup etc. If the  lumber is not frozen, You have to take 10 or 11 degree hook angle and to set teeth for about 0,025inch, for lubrication it is enough plain water, if you add a bit of soap then it would be enough one bucket of water for about half a day.  If the lumber is fully frozen then I'm preparing my blades like for hardwoods - 7-8degree angle, smaler tooth height, and tooth set about 0,015". If the fir is not fully frozen, then frozen part I'm sawing with one blade, and not fozen part with other, it is not fast to change blades twice per one log, but the customer satisfaction and straight cut for me is in the first place...

[Brucer]

Keep in mind that Douglas-Fir is not a fir at all. It's completely unrelated to the true firs.

[Art_H]

Yeah... Round here in some places West facing, and dry, you can literally drill and tap the Douglas Fir.  When dry you can hardly put a nail through it.  Beautiful wood though.