INAUGURAL OUTING YESTERDAY

Tom Posch · December 16, 2018, 01:02:56 PM

Used the sawmill yesterday for the first time. Saw cuts wavy. I think I know why. I have a bunch of large (30"+) oak stalks in the yard. Not wanting to waste good raw material, I cut the lower portion off. The upper part has a bunch of branches shooting off. It seems the saw would climb at these crotches. I tried to tighten the blade tension. It made no difference. I am not sure I have a good blade. It is the one that came with the saw. It feels plenty sharp to the touch.

My question is, do I have a saw problem, a technique problem, or am I just using bad raw material?

I threw a small piece of pine on the table and it cut pretty nice.

Have to gather some tools and supplies up, but was very cool!

terrifictimbersllc · December 16, 2018, 01:12:40 PM

Could be many things but most likely the blade is not sharp enough for the task at hand. It might not cut flat in wide material but do so well in narrow material if it has dulled a bit. Feeling sharp doesn't tell much. Your best investment in that regard is to get a 10x hand lens. With it you can look at a tooth. It should have no glint or roundedness along the line where the front face and back face meet. Or be rounded over at the very outside edge of this line (outside edge of the tooth). If you have a lens and some fresh blades, compare them with the used blade. And maybe save one of those blades for a while as a reference.

It can take almost nothing other than cutting a few inches of dirty wood, to dull a blade to the point where it will not perform well on wide especially crotch or knot grain in some woods. You may have cut some dirt already with the blade you are referring to. If you have a debarker maybe the front of the log was dirty, where the debarker can't reach. It is also quite possible to have a blade you think is sharp, not cut flat, and on inspection of the blade with the lens, find out that it is not adequately sharpened. Exception rather than the rule for sure, but not uncommon.

Den-Den · December 16, 2018, 01:47:45 PM

"My question is, do I have a saw problem, a technique problem, or am I just using bad raw material?"

It might be an alignment issue, if the alignment is just a little off it will make narrow cuts perfectly but wide cuts are wavy. The same thing happens when the blade is starting to dull. When everything is perfect, you should be able to make wide cuts through knots without deflection but ONLY when everything is perfect. Other things to check:
* Drive belt tension
* Engine RPM
* sap buildup on blade

Tom Posch · December 16, 2018, 03:16:35 PM

Quote from: Den-Den on December 16, 2018, 01:47:45 PM
Other things to check:
* Drive belt tension
* Engine RPM
* sap buildup on blade

Belt is tight. Engine was wide open. Not sure the RPM. No sap. I didn't use water though.

cwk266 · December 16, 2018, 03:47:01 PM

I am not an expert by no means and found myself having the same problem of no band-saw mill experience and cuts going wrong.The sharpness of the blade is huge as has already been mentioned I found that the type of blade guide and how it was adjusted played a part in the problem I was having.I switched from bearing type guides to ceramic blocks which was an improvement and I think that if I was to continue using that mill I would have changed one more time to a Cooks sawmill type of blade guide.It seemed to me that in the process of learning the Cooks blade guides should have been my first choice but did not know it.Take my comments as coming from a newbie not advise from a expert

DPatton · December 16, 2018, 06:00:47 PM

Congratulations on the Linn! The first day is always exciting and usually filled with questions. Since it was your first day of running the mill I wouldn't get too discouraged, for there is a big learning curve ahead and sometimes it takes a while to work out the bugs and understand how to troubleshoot different cutting issues. If you are tackling 30" wide oaks with crotches your blade and adjustments need be in tip top fourm. It's not unusual for a band to want to try and follow the grain of the wood at a large crotch or knot. But with time running the mill you can learn how to get it to saw flat and straight. From your description if the RPMs, belt tension, and band tension are correctly set some things I would ask:
1, Are the logs your cutting freshly felled and green or were they from a dead tree or been down and drying for some time?
2, Are the cuts wavy throughout the whole length, only at the start of the cut, the crotch portion, or at the end of the cut?
3, Does lube help calm down or eliminate the waves?
4, Does putting on a new blade make a difference?

Hopefully you were able to saw some logs today and figure out the issue. One thing that I found with my mill a few years back was I started using a 36" long aluminum straight edge clamped onto the tensioned blade to adjust my guide rollers (learned right here on the FF). This allows me to adjust the blade so it is dead level with the bed. Before that I was following the owners manual procedure for this adjustment, and it wasn't nearly as accurate.

WV Sawmiller · December 16, 2018, 06:50:34 PM

What was the hook angle on your blades? I like 4 degree blades for hard woods like oak and even when cutting soft spruce with hard knots.

Tom Posch · December 16, 2018, 06:56:11 PM

Quote from: DPatton on December 16, 2018, 06:00:47 PM2, Are the cuts wavy throughout the whole length, only at the start of the cut, the crotch portion, or at the end of the cut?
3, Does lube help calm down or eliminate the waves?
4, Does putting on a new blade make a difference?

The logs were dropped about a month a go.
The waves run full length.
I did not use water.
I'm getting blades this week.

Thanks for your input.
Tom

Tom Posch · December 16, 2018, 07:01:46 PM

Quote from: WV Sawmiller on December 16, 2018, 06:50:34 PM
What was the hook angle on your blades? I like 4 degree blades for hard woods like oak and even when cutting soft spruce with hard knots.

Not sure hook angle, but it's very slight, I'd say 4*.

Southside · December 16, 2018, 07:45:39 PM

From your last answer it sounds like your band is dull. I run lube in oak, especially 30" oak. Don't get discouraged, you all but started with a worse case scenario. I guess you could have tossed a dry Hickory crotch piece on there that had been drug through the mud just for extra fun to really up your game.

Even clean looking logs have sand and dirt buried in the bark, especially deep furrowed species like oak. Try sawing a "clean" at log at sunset one evening and watch all the little sparks that zing off the bark.

One more thing that can cause waves is cutting too fast, or too slow. Too fast and you are over running the band, too slow and you create excess heat which causes the band to expand and loose tension.

It's a learning curve, you will get a feel for the sound of the engine, the sound of the band cutting the wood, the look and texture of the sawdust. You will be able to tell when a band starts to get dull, you can even tell the difference in how the band enters the log when it gets dull. You want to change your bands before they are dull, basically you want to take them off just as they begin to loose their edge, you will get better lumber, longer band life, more sharpenings, and overall lower cost of operation this way. It may feel counter intuitive to do this, but it pays dividends.

Banjo picker · December 16, 2018, 07:55:51 PM

Don't worry too much about it untill you get some new blades. You said they were on the way. It would be prudent to get something smaller than 30 inches to learn on as well. Banjo

terrifictimbersllc · December 16, 2018, 09:07:29 PM

If the cut is wavy due to a dull band, a sharp band, everything otherwise the same, run back over the same surface at the same height, will often cleanly cut off the humps left by the dull band. Sharp band cuts those humps off, flat as can be.

No amount of skimming with the old band at different speeds etc, will do the same thing. Impressive demonstration and verification of the importance of sharpness.

John Bartley · December 16, 2018, 09:15:13 PM

My experience with wavy cuts is this :

Given that the "setup" is correct ie: correct tension and alignment,

A dull, properly set band will cut slowly but straight, without waves.
A sharp, improperly set band will cause waves whether cutting fast or slow.

cheers

Tom Posch · December 17, 2018, 03:06:27 PM

I've heard "alignment" a couple times. How is that done? I see a way to adjust the pitch or angle of attack on the blade. How is it checked? If you stand back and look at the saw from the side, it looks like the top of the saw is leaning out more than it should be. It may have gotten knocked out in transport. I bought it 600 miles from home.

Chuck White · December 17, 2018, 06:48:11 PM

Your owner/operator manual should show you step-by-step instructions on how to do a complete alignment!

YellowHammer · December 17, 2018, 10:54:16 PM

You should get a blade alignment tool if you don't have one. Its a small bar that clamps to the band and allows you to make specific measurements to insure the blade is parallel and level to the mill bed. If there is any angle of attack, especially if it is more than the set of you teeth, the band will not cut straight.