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Wavy cuts .

Started by shortlogger, March 04, 2017, 04:26:55 PM

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shortlogger

I usually just cut pine and cedar but today I'm sawing up some hardwood for a couple of trailers but the lumber is coming out pretty bad wavy . All I have is 10 degree blades so is that my problem or could it be the timber itself? It's Water Oak .
1 Corinthians 3:7 So then neither he who plants is anything, nor he who waters, but God who gives the increase . "NKJV"

BigDogTreekillr

I have better luck sawing red oak with a 9 degree blade then the 10's. Want to try the 7 but not sure I have enough hp to do so. Also feed rate seems to help with the wavy cuts. Faster the better
Mopar Go Far! Whoopaaa

WV Sawmiller

   I'd certainly try some 4 degree blades if it was my mill. More details about the type mill, hp, etc would be helpful.
Howard Green
WM LT35HDG25(2015) , 2011 4WD F150 Ford Lariat PU, Kawasaki 650 ATV, Stihl 440 Chainsaw, homemade logging arch (w/custom built rear log dolly), JD 750 w/4' wide Bushhog brand FEL

Dad always said "You can shear a sheep a bunch of times but you can only skin him once

drobertson

Not sure what mill you have, but I'm thinking it something other than hook angle with this, either drive belt tension, feed speed,  or blades that may be not quite all there edge wise,
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

slider

And there is alignment to think about.
al glenn

Knute

The one time I had a wavy cut I increased the blade tension and solved the problem. But could be any of the previous things mentioned also.

pineywoods

wavey cuts happen when the blade twists. There are many things that make a blade twist. Top of the list is dull teeth...
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
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shortlogger

I just finished a pine log before I put on the hardwood and it was cutting perfect. It might just be that the hardwood was affected more by a slightly dull blade . I'll put on a new blade before I do the next log and see how it goes . So on feed rate am I better off to go fast than slow ? I was taking it easy and barely even loading the motor in the cut , I could go a bit faster no problem. I've got a 30 hp Kohler on a manual logmaster mill .
1 Corinthians 3:7 So then neither he who plants is anything, nor he who waters, but God who gives the increase . "NKJV"

bandmiller2

Wavy cuts are what a band mill does when its not happy about something. Our problem is knowing what its fisted off about. As ole Piney said dull teeth is no. 1. Myself I think its mostly different densities of wood be it from tension, knots or hard spots. I can cut a cant of white pine until the band starts to wave around knots then throw on an oak log (red) and get perfect cuts. Try a new band and a different log you will probably find your problems have left. Frank C.
A man armed with common sense is packing a big piece

Carson-saws

Is there a verdict or is the jury still out?..Would be interesting, to me anyway, to see a grid of who uses what for what...hardwoods....soft woods....which configuration is the most advantageous/applicable?
Let the Forest be salvation long before it needs to be

Rougespear

I've always read (haven't tried) that softwoods expose the weakpoints in the mill sooner than hardwoods (ie: blade guide alignment, sharpness, etc.).  I would vote that sharpness and guide alignment should be a priority to check first.
Custom built Cook's-style hydraulic bandmill.

esteadle

Always change blades as your first troubleshooting measure if you get wavy lumber.

Check the sharpness and set of the blade by inspecting it in bright light. Dull teeth reflect light from the point of the tooth. A sharp tooth will not reflect any light. Test sharpness by pushing the teeth of the blade into a small block of softwood and then picking up the wood with the blade. A sharp blade will penetrate the wood enough to embed itself and you can pick up the block of wood with just the blade. Check the set of the blade with a dial gauge or micrometer... the set should be about 1/2 of the thickness of the blade (so a .042 blade will set at about .021 +/-0 to taste).

Blade tension is also a good thing to check, but you should have a guide or spec for the correct tension already set up. You can often run a dull blade a little longer without getting waviness if you increase tension, but you'll reduce the overall life of the blade by doing so... it's a trade off.

If you still get wavy cuts after changing out the blade for a good sharp one, then check your blades parallel to the head tracks. With a blade on the mill, set to the correct tension lay a long (24" or longer) steel ruler on the top the blade parallel to the head tracks. Take care to set it on one of the un-swaged teeth (or the blade will angle up or down with the set of the tooth it sitting on). Now measure the height of the front and back of the rule -- off of the bunks. The measurements should be exactly the same. If not, adjust the pitch of the roller bearings to get them exactly the same.

I have never been able to fix wavy boards by feeding faster. I just end up with ruined lumber, and stuck / broken blades that way. Maybe that works with other mills. Not mine (Timber Harvester 30HT26 1.25" width blades).



Brad_bb

For lower power mills like my 18HP LT15, it's recommended to use 4 degree.  Think about it, a 10 degree is a more aggressive angle.  It's going to try to bite in more, so as Woodmizer explained to me, it takes more power to pull it through the cut.  4 degree is less aggressive.  Sure you can still get a wavy cut with a 4 degree, but not as much as higher angle bands.  After tooth angle and mill HP, tooth sharpness is next culprit, which is why everyone's first reaction is to change the band.  It usually works.  Lastly you want to check your drive belt tension every 20 hours.  I hadn't checked mine for 100 hours and it was way out of spec, which might explain some problems I had.  Band tension should be set correctly too.  Make sure you use your blade guide to support your blade.  Have the throat open only what you need.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

gww

Shortlogger
I always used 10 degree blades even with a nine horse motor.  I have an 18 horse now and just started using 8 degree.  I had some wave and had two things wrong.  I had a guide bearing that I had tightend the nut on and it heated up and had slack in it.  I also had a lose drive belt.  I tightened the belt and changed the bearing and all is good.  I tightened the tension a little to but wish I hadn't after seeing the belt and bearing. I am pretty sure it was the drive belt loseness causing most of the issue.  The new bearing in the guide didn't hurt though.

I believe you can cut strait with the 10 degree if all things are right and it is sharp.

So if you have tried some of the things others have mentioned, I say look at all connections to your guide system and make sure there is no wiggle any where.  Also check the bearings and see if they alow slop.

I have a rickety home made mill and guides or guide brackets coming lose or slipping due to nut loseness and drive belt slipping are what I have seen cause wavyness.  Every once in a while I will have a log with so much inner stress that I can't do it well but that is rare.

bearing freezing will make the blade act funny also.

I had thought that I had read that it took more power to run a seven degree blade but maby that was just the seven degree turbo blade or I could be immagining things.

I don't immagine the importance of guide stiffness being important though.

I hope this helps in some way.
Good luck
gww

Ps I also slow down, not speed up when I start getting a little wave.  I have tried both.

shortlogger

I've not got a chance to get back on it yet been really buys but I'll probably work on it tomorrow. I have plenty of things to look at now . I'm gonna inspect everything when I pull my blade and then start ba k with a new one .
1 Corinthians 3:7 So then neither he who plants is anything, nor he who waters, but God who gives the increase . "NKJV"

shortlogger

I started back cutting with a sharp blade and it's doing much better but still not as good as I would like . This dang hardwood is a pain to cut seems like it wants to warp every wich way possible. The outside couple of cuts off each side come off pretty good but it seems like no matter how much I flip it I keep getting warped boards and cants . My cull pile is almost adding up as fast as my lumber pile, it's a good thing I burn firewood.
1 Corinthians 3:7 So then neither he who plants is anything, nor he who waters, but God who gives the increase . "NKJV"

gww

Shortlogger
QuoteI started back cutting with a sharp blade and it's doing much better but still not as good as I would like . This dang hardwood is a pain to cut seems like it wants to warp every wich way possible. The outside couple of cuts off each side come off pretty good but it seems like no matter how much I flip it I keep getting warped boards and cants . My cull pile is almost adding up as fast as my lumber pile, it's a good thing I burn firewood.

Selling some of that said fire wood is the only thing keeping me in blades ;).

Cheers
gww

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