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Blade "diving" into the log

Started by 50 Acre Jim, March 09, 2018, 04:44:14 PM

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Ga Mtn Man

Jim, in a previous post you stated that the blade is level to the bunks.  To be clear, "level to the bunks" means that the blade is running parallel to the bed of the mill lengthwise.   How did you check this?  Do you have a blade alignment tool?  I agree with LeeB, you should be able to cut straight even without guides, especially poplar.  
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

Nomad

     I'm with GMM.  Your drive belt is also the one the band sits on, right?  All I can think of is that either your band is running far enough back on the wheel to take the set out of the teeth (unlikely) or one of your roller guides it slightly tilted up or down.  That seems like the culprit from where I sit.  A blade guide alignment tool would identify that in short order.  Making a suitable substitute wouldn't be hard to do.
Buying a hammer doesn't make you a carpenter
WoodMizer LT50HDD51-WR
Lucas DSM23-19

Magicman

 

This is not the Wood-Mizer way but it works if the bed rails are all level.  The "Blade Guide Alignment Tool" (BGAT) allows you to insure that the blade is perfectly aligned with the sawmill bed rails.  Open the blade guide arm completely and check and insure that the blade is absolutely horizontal at each blade guide roller.

Yes, the sawmill should saw straight even without blade guides, but it needs a good (sharp) blade to do so.  

You have mentioned "taunt" several times, but that does not accurately describe "how" taunt.  In your video you turned the roller blade guide easily by hand.  This should be virtually impossible to do. 

To properly saw the drive belt must not slip which will slow the blade speed down.  As Steve has mentioned several times, the blade guides must be ¼" below your blade wheels.  The blade must be tight, not taunt.  The blade's vertical tilt must be adjusted so that the blade is horizontal to the bed rails (as illustrated above).    Your blade guides should have a slight horizontal tilt toward the idle side.  Your blade must be sharp and properly set.  Match your blade hook angle to the log species.  Don't push your feed rate beyond your engine's hp capability.

Insure that the above items are all in order and your wave problem will disappear.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Skipper11A

I notice that all the users recommending ¼" down pressure with the roller guides are all Woodmizer owners.  But Jim has a Norwood and Norwood designed their guides without any down pressure.  Same on my EZ Boardwalk and many other mills and they all cut straight boards.  That saw should cut straight without any roller guides at all, so obviously the problem lies elsewhere.

Jim, since you've checked everything for alignment, sharpness, etc, I'm thinking that the only thing left that would cause that problem is lack of blade tension.  I suggest you over tension the blade and see if it doesn't resolve your issue.  This possible solution has the added benefits of being easy and free!

Skipper11A

I missed this earlier, but Starmac's had this problem and his solution was to increase blade tension (and simultaneously pull his hair out).


Quote from: starmac on April 19, 2018, 07:38:50 PMI would be pulling my hair out.
The only time mine ever cut anything remotely like that is when I first got it, I was not tightening the band as much as I thought, or at least not as much as it needed to be, but it would still cut pretty much fine, but start waving pretty quick as it started dulling.

Jim, you also mentioned you got different instructions for blade tightening from the factory rep than what you had been using.  I'm betting that the blade is still not tight enough and that you just haven't found the right tension yet.

pineywoods

Short story, you get dives when the blade twists for whatever reason. Figure out why the blade is twisting and you will have the problem solved. Most common cause is forcing a dull blade into the wood, which forces the blade back into the guides, plus changes the blade tracking..
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

Tin Horse

Prior to learning plenty on this forum I followed cooks videos for setup on my Enercraft. I bought the blade alignment tool and tension gauge. The alignment tool would be easy to make but it was cheap enough. I agree it should cut straight without the guides but they're there for a reason. I've got 1/4" down pressure on mine. I have little literature on my mill so I wanted to know what tension I've been running. Been going by the alignment mark on the spring tensioner. With the tension gauge I now see I've been running at about 3500 psi. Kinda high from what I believe it should be. Put it down to about 2800 psi and it seems OK. At least I know tension and can always verify it. I guess some mills have dial gauges built on them. I'd definitely like that. 
Bell 1000 Wood Processor. Enercraft 30HTL, Case 580SL. Kioti 7320.

Magicman

Quote from: Skipper11A on April 20, 2018, 10:15:41 AMI notice that all the users recommending ¼" down pressure with the roller guides are all Woodmizer owners
Wrong.  Steve, (ladylake) owns a TimberKing B20.  

There is something seriously missing in this entire "wavy board" situation.  Norwood sawmills, as set up from the factory, will and do saw straight lumber every day.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

WLC

Quote from: pineywoods on April 20, 2018, 10:41:25 AM
Short story, you get dives when the blade twists for whatever reason. Figure out why the blade is twisting and you will have the problem solved. Most common cause is forcing a dull blade into the wood, which forces the blade back into the guides, plus changes the blade tracking..
Found this out for the first time yesterday.  Knew the blade needed changing, could feel it, but wanted to finish the log I was in. Should've stopped and changed the blade when I first felt it getting dull.  Pulled the stack of 4 2X6's off and two of them had waves or dives at a knot. Didn't ruin the lumber, but I am glad I wasn't sawing a birch slab, or sawing lumber for someone other than myself.
Woodmizer LT28
Branson 4wd tractor
Stihl chainsaws
Elbow grease.

ladylake

 

  Both WM and Cooks recommend 1/4" down pressure, TK recommend 1/8"  but that got changed to 1/4 right after I got my mill as it saws straighter with 1/4".  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

OffGrid973

Had this happen on manual mill before my concrete slab was poured because different logs caused bed to flex.  Even though it was level when nothing was on or running. (Check this first)

Also blade tensioner loosened once in my LT-10 (actually snapped) and after I realized that was there for a Very Important reason I check it each startup for tightness...no more wavy lines. I tried a bush fix with eye bolts and nuts, get the right tensioner from the factory; and keep one on backup.

And lastly what MM said, slow down to a crawl and cut once at a foot per 10sec rate and see if it comes out straight.  This way you are taking the extra factors caused by "stress" out of the equation.  Like letting a chainsaw cut without pushing, sharp blade should not go sideways if working correctly.

Your Fellow Woodworker,
- Off Grid

Skipper11A

While it is interesting, none of this discussion about roller guide down pressure will help Jim identify his problem.  I think we all agree that his saw should cut straight without any blade guides at all.  So the problem must lie elsewhere.  More to the point, I think that having Jim adjust his guides is an incorrect diagnosis for his problem.

As I work down my troubleshooting checklist, I think that Jim has verified that the blade is sharp and the wheels are in alignment, but I'm not sure that he has checked off the box next to "Proper blade tension".  I know he addressed the blade tension, but I didn't get the impression that he had fully ruled this out as an issue.  So increasing blade tension would be my next troubleshooting step.  In fact, he should lubricate all of the blade tensioning equipment on his mill as this could simply be an issue of lack of lubrication.

SawyerTed

After ensuring the blade tension is correct, I would check to make sure something isn't taking the set out of the blades. Originally the problem appeared after Jim had blades sharpened by a local guy.  New blades cut fine (see his original post).  At that time it appeared to be faulty sharpening/improper set.

Now he has the problem with a new set of rollers and new blades.  The video of the wavy cut makes me think something is flattening the tooth set.  Could be my inexperience with sawmills but my woodworking experience leads me this way.

If the blade loses its set on the inside (the side against the wheels) wouldn't it want to cut to the outside aka dive?
Woodmizer LT50, WM BMS 250, WM BMT 250, Kubota MX5100, IH McCormick Farmall 140, Husqvarna 372XP, Husqvarna 455 Rancher

LeeB

What does the sawdust between the cant and the board look like? Fine and loose or packed tight? Insufficient set would leave packed dust in the cut. I still think the dive belt is slipping, weather that be on the drive wheel or the blade itself slipping on the drive wheel. Does not the Norwood use the drive belt as the wheel belt as well? Change the belt.
'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

Remle

Quote from: 50 Acre Jim on April 19, 2018, 06:54:05 PM
Well, I tried the recommendations I got from Norwood support.  One was to thaw out the cant and to try a brand new blade.  So I put up a 12" poplar that has been in the sun all day.  Soft wood, very much not-frozen.   Brand new Cooks blade.  

Here is a video of what I got.

https://youtu.be/y_nI45_dIgs

Blades should run flat on the entire surface of the guide rollers. Pictures can be deceiving, but in your picture their is a shinny streak along the front of the roller the length of the blade. IMHO this would indicate the blade is not running flat on the roller and pitched at an angle is causing it to dive. In the dark, shine a light under the roller and see if it has full contact to the roller's full width or if it is indeed twisted or you can check with a "Blade Guide Alignment Tool". Again it may just be an illusion in the picture.

homesteader shane

I m running a norwood with the same set up and had the same problem last summer. after discussing it with the guy the dose my sharping for me we found the problem. On a norwood mill the roller guides are just that "guides" they are not meant to hold the band. after checking everything we found the roller guides had worning down from front to back and where guiding the band down. after replacing the rollers it ran great for about 2 logs then same thing "diving". I discussed it again with the sharping guy he told me to "get the used band off the mill and try to coil it". BINGO it didn't coil up easily. turns out when it started to dive from the worn out rollers I would over come that problem by tighting up my bands more and by over tighting them. the bands lost some temper. the old bands would sharping and cut fine till the heated up the they would lose set. costly lesson learned. with the new rollers and all new bands it cuts straight as an arrow again.

check you roller guides with  calipers they cant be more then 1/10000 out from front to back. I replace them every fall now. but im doing a ton of milling and use the bands for you self and when they start to dive. throw them away
nothing wrong with reshaping( i use bands till they  done. usually 4 to 5 sharpings) but for whatever resin your bands have lost the temper in the steel and will never wok properly again.

and make sure the bands are running about 3/4 on the belts. if the teeth of the band are running to close to the belts it will also take the set out. and the backs of the roller guides should be a 1/4 inch from the back of the band

Magicman

One item that I have not seen mentioned is buildup on the blade.  In the video and also in the pictures on the previous page I am seeing some buildup.  It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.


Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Skipper11A

Quote from: Magicman on April 21, 2018, 02:26:25 PMOne item that I have not seen mentioned is buildup on the blade.  In the video and also in the pictures on the previous page I am seeing some buildup.  It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.
Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.
MM has sharp eyes. At 1:10 in the video you can clearly see the buildup, shiny to the left of the blade guide, but just dark crap between the guides. This is the shiny streak that Remle noticed.  It doesn't look like enough to affect the cut in softer woods but I wonder what the outside of the blade looks like.

50 Acre Jim

Took a power washer to the mill and cleaned every bit of build up anywhere on the machine.  But it made no difference in how the machine cut.  

When I spoke to support at Norwood, they suggested some things, all of which I tried with no change in cut.  Their final suggestion was to change back to the ceramic guides, which I did yesterday morning.  It made a little bit of difference. I found that if I cut extremely slow, and I mean extremely slow, I can push the blade through the log with minimal waviness.  

The product wouldn't be acceptable for sale; no way anyone would want to buy it.  But I did at least get a few boards cut to finish a deck that I had been building.  (Nothing makes me angrier than to have to buy lumber at Lowes because my mill can't produce what I need.)

So the ceramics made a little difference, but they aren't fixing the problem, just masked it a bit.  What I have noticed though is that the three planks I cut yesterday have a washboard look to them. Saying "washboard" probably doesn't really describe the effect I'm seeing, it's more like the cutting edge, or teeth, on a file.   I know it's an exaggeration, but if I could pick up the plank and flip it over, I could use it to file something.  

I'm going to dismantle and reassemble the bed this weekend.  May do the same with the carriage.  Not sure what the next step will be if all this fails but given there is no Norwood support in my area I may be faced with a new purchase.  There is a limit to every man's patience, and I've found mine.

Go to work?  Probably Knott.  Because I cant.

LeeB

Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands? Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps? Have you tried any other batch of blades than these two? Have you tried changing or adjusting the tension of the drive belt? You don't have to see the belt slipping to be loosing blade speed. Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log? Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.
'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

ladylake

 

 I don't mind sounding like a broken record, you need to put 1/4" down pressure on those roller guide no matter what it takes.  Without down pressure you may as well not use them.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

LeeB

On the mill I mentioned in my last post the guides were set at 1/4" down pressure and I still had the wavy cuts until I got the blade up to speed by changing the belt. 
'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

ladylake



 For sure there can be other problems, but it's not going to cut straight with no down pressure plain and simple. That is the first thing to fix.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

50 Acre Jim

Quote from: LeeB on May 02, 2018, 07:34:42 AM
Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands?    
A: No, I have used Norwoods blades, resharpened Norwood blades and now brand new Cooks blades.    Problem persists.

Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps?    
A:  No, blades have come from several sources.

Have you tried changing or adjusting the tension of the drive belt?  
A:  Yes, I have adjusted the tension of the drive belt, I have dissasembled the bed and reassembled it.  I have used both the roller guides and now I have put the ceramics back on.


Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log?
A: No decrease in engine speed.  Sound is consistant.


Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.
LeeB, I answered your questions in your quote as it was easier to address them individually.
Go to work?  Probably Knott.  Because I cant.

50 Acre Jim

Quote


I don't mind sounding like a broken record, you need to put 1/4" down pressure on those roller guide no matter what it takes.  Without down pressure you may as well not use them.  Steve
I have removed them, Steve.  I am now working with the factory default ceramics.   I see a little difference, but I think it's just that the ceramics are helping to camouflage the problem.    I am now in the process of disassembling and reassembling the carriage.  Hopefully, whatever it causing the problem will get fixed along the way.  :-)
Go to work?  Probably Knott.  Because I cant.

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