Visible saw marks on softer wood?

[Woodslabs]

Hi all,

I am cutting poplar for the first time and am getting visible saw marks.  But around knots the saw marks go away and i get a smooth cut.  I am using .55 blades that i use for very hard woods.  I run a LT15 wide.  I dont think the blade is the issue as i am getting no wave.  Anyone knows whats going on?  Is this common with softer wood?

When i mill Oak or walnut i get a smooth cut.

[Ox]

It could be pitch buildup forcing the blade to cut a little off from plumb.

[fishfighter]

Could have a bent tooth on the blade. Had one do that to me before and it was a new blade.

[bandmiller2]

Almost always its a tooth or teeth with too much set. Even new bands coiling and uncoiling can push some teeth out of set. If the marks are close it indicates many teeth, spaced far apart the inverse. Frank C.

[bkaimwood]

In my experience, most likely two causes...first, feed rate too slow... Most people slow down when they see these, making it worse...try sawing faster and see what happens, an easy one to eliminate... Second would be blade chatter, most likely caused by now enough tension... There are other causes, but IMO, those are most likely...would need to know what king of mill your running to go further...less hook on softwoods for sure...

[Woodslabs]

It wasn't the blade as i changed the blade and the issue continued.  I found that if i did not take the slabs off and continued cutting the next slab the issue was gone maybe due to the weight of the other slabs.  I will try cutting cherry tomorrow and see if it continues.

What do you mean by pitch buildup?


I'm running a Lt 15 wide.  Blade: I run .055 x 1 1/4 x 180, 9 degrees, 176 length

I may have been running it too slow as i am use to cutting hardwoods.


Saw is a month old or so.

[fishfighter]

pitch build up = sap build up. More lube to wash it off/out.

[GeneWengert-WoodDoc]

Poplar, which is also called aspen and popple, is a very soft , weak wood, so the fibers will often bend over instead of being cut.  This gives you the saw marks you are having. 

Three ways to reduce this effect. 
First, use an aggressive feed.  Slow feed will have more of this. 
Tsecond use very sharp saws.
Third, 7 degrees is a bit too small for a softer, low density wood like aspen.   Try 10 or 12 degrees. The smaller angle Works well for dense wood.  The area around a knot is dense and strong and that is why the knots cut ok at 7 degrees.

General Guidelines
4 degree: frozen dense hardwoods with high powered mills
7 degree: frozen logs and high density species with medium to higher powered mills
9 degree: medium to higher density species, especially on lower powered mills and smaller logs
10 degree: all purpose (but some slight compromising) for medium and lower powered mills
12 degree: medium to low density species
13 degree: lowest density species

Questions?

[Chuck White]

In my experience, most likely two causes...first, feed rate too slow... Most people slow down when they see these, making it worse...try sawing faster and see what happens, an easy one to eliminate... Second would be blade chatter, most likely caused by now enough tension... There are other causes, but IMO, those are most likely...would need to know what king of mill your running to go further...less hook on softwoods for sure...

I believe this is correct!

When the marks stop near knots, it says to me that the engine rpm increases, causing the blade fpm to increase, thus the teeth are engaging the wood a little heavier.

Try sawing and pushing your feed speed just a little harder.

[WoodenHead]

In my experience, most likely two causes...first, feed rate too slow... Most people slow down when they see these, making it worse...try sawing faster and see what happens, an easy one to eliminate... Second would be blade chatter, most likely caused by now enough tension... There are other causes, but IMO, those are most likely...would need to know what king of mill your running to go further...less hook on softwoods for sure...

I also agree.  Most likely feed rate too slow.  I use a 10 degree blade for Aspen, Basswood, and the other soft hardwoods. 

It is also very easy not to have enough tension on an LT15 (or LT28 which I used to have).  There is no way to know for sure what the tension actually is unless you have special measuring tools.  The LT40 is much better that way, since it has a gauge.

[Woodslabs]

Poplar, which is also called aspen and popple, is a very soft , weak wood, so the fibers will often bend over instead of being cut.  This gives you the saw marks you are having. 

Three ways to reduce this effect.  First, use an aggressive feed.  Slow feed will have more of this.  Two, use very sharp saws.  Three 7 degrees is a bit too much for a soft wood like aspen.  Try a smaller angle.  The smaller angle does not work well for dense wood.  The area around a knot is dense and strong and that is why the knots cut ok.

Questions?

Thanks! this is what i thought.  I was running it slow like i would cutting oak.

Quick question about the roller guides.  I assume that the blade should be touching the guides and they should roll as you cut correct?

[Ox]

Quote:  I assume that the blade should be touching the guides and they should roll as you cut correct?


Absolutely.  My mill calls for 1/4" down deflection.  I'm not sure about Woodmizer, I think it's about the same.  This puts down pressure on your blade and controls the blade.  And yes, they should be rolling as the blade turns.  I'm thinking it should be in your owner's manual someplace, the proper adjustments or whatnot.

The other guys are 100% right with the softer wood needing a faster feed rate.  I had forgotten all about this but now clearly remember sawing slightly punky red pine and ran into this very same issue you're having.  Doubled my feed speed and all was well and smooth as rough cut can be. 

[bkaimwood]

Just a note regarding Gene's previous quick reference chart...awesome chart, love it!!! But to the fellas running higher horsepower mills, in can be deceiving... Great chart for 75% of the mills out, but never forget that nothing is written in stone, and don't forget how easy it is to experiment with your own mill, they all vary to some degree. Thanks again for the chart Gene.

[GeneWengert-WoodDoc]

Thank you for including the qualifying comments that I should have added myself.  You are totally correct.

What I should have said...  A reader should get a feel for the relationship between angle and wood density, but the best angle for a mill depends on the mill design and operation, and the operator's preference as well.

[bkaimwood]

Anytime Gene...frankly, I am honored to be able to add anything constructive to a post of yours. I am guilty of not always taking my own advice, as we all are, and forgetting to stop, think, and experiment with a thing or two...it takes a bit more time, but is usually the best teacher... Especially in special situations. Having such a great forum, with like minded individuals, is priceless, but we need to remember not to rely too much, especially for novices like me. We have such strong members that can help us with most anything, but don't want to count on a forum to run our saws for us.

[ladylake]

Keep in mind you are sawing rough sawn lumber, nothing wrong with saw marks .  steve

[Ox]

Keep in mind you are sawing rough sawn lumber, nothing wrong with saw marks .  steve

x2 on this one, for sure.  Perfectly smooth boards require additional steps (planer, jointer, etc.).
I personally like the way rough cut looks and build with it all the time.  I like the rustic looks.  As an additional plus, anything that looks rough makes me look less rough.  :D

[Magicman]

I had a customer that wanted a non-skid finish on stair treads.  It just so happened that I had the perfect blade.  ;D

[Ox]

I milled some very wide black cherry slabs yesterday, they were around 32" across, 10/4 thick.  I had pretty bad oscillation marks coming and going through the cut.  I changed to a new blade and that helped but still had the marks.  I increased tension from the recommended 2900 lbs on the blade to 3200 and it all went away.  Hopefully this is useful information.

MagicMan -  :D

[Andries]

I was asked for some wide and long 5/4 boards last week.
This is 35 feet long and varied from 22 to 27 inches wide.

Western Red Cedar is very soft, but found that if I bumped up the blade tension a bit, the cut smoothed right out.
As has been said earlier - its tension, blade angle, blade lube/cleaner, engine power, etc.
Experience and experimenting a bit will show you what works in your situation.

[bkaimwood]

I've found the same thing, Magicman... Don't be scared to run that tensioner guage well past it 3k lb limit...in really rough stuff, I run it at 6:00, with no problems, only success...