Why is my cherry burning?

[jaustin]

Why is my cherry burning?
I thought the blade may be dull since the blade has cut alot of wood.
I went out and bought a new blade and it stills burns.
It is on a ridgid radial arm saw.
I have went slow medium and fast thru the wood.
I have checked square and it appears to be squared.
so what am i doing wrong?

 

[McRabbet]

You may be cross-cutting through the pieces too slowly. Yep -- too slow. Try cutting through a little more aggressively on some scrap pieces first.

HTH -- Rob

 

[Ken Weaver]

Ordinarily I would have suggested the things you have already checked. Since you did that, do you remember what you were doing on those cuts that didn't burn? Maybe you went slightly faster than those the did burn? I would usually suspect feed rate, I suspect that is still behind it.

 

[Grgramps]

John, First let me explain that I don't own a radial arm and have had little experience with one. Ken and Rob have made good suggestions. If their ideas don't resolve the problem, try to determine if the blade is perfectly aligned with the path that it is taking i.e. 90 degrees. If the trailing edge of the blade is dragging as it comes through the cut it will most certainly burn regardless of how sharp it is.
Cherry is one of my favorite woods to work with and I keep my tools sharp. Nevertheless, I get burn marks if I'm not giving it 100% of my attention. Sometimes I think it burns because I look at it too hard.
Roy
P.S. I have noted however that I don't get burn marks using a hand plane or chisel.:lol:

 

[Big Mike]

Any climbing going on while you were cutting? Sometimes a radial arm saw wants to grab the wood and climb and that results in a binding/burning cut.

Is the blade grabbing as you cut? Perhaps the tooth configuration you are using is too fine for this operation. Sometimes for rough cuts on a radial arm saw, I never use it for finish cuts as I don't find them to be very accurate for long, I use a combination blade and although I don't get quite as smooth a cut I don't get the burning either.

Is your radial arm flexing as you cut/are you pulling straight as you cut? Both of these situations will cause the blade to pinch a little and get burn marks like the ones you have pictured.

Is your fence straight? Seems to be a ridiculous question but if it is not straight then as you cut the wood while pushing against it to hold it against the fence when enough wood is cut the remainder of the piece can flex and that can pinch the blade.

Is your wood straight/jointed? If it is slighly bowed, even a little bit, when you cut part way through the remainder can flex and that can pinch the blade.

Sometimes cherry just wants to burn but usually when you see burn marks like you have the blade is pinched during the cut somehow.

 

[DaveO]

Cherry is bad about burning. The wood has a high sugar content. In addition to your feed rate you might want to check that you don't have a toe in or out on the blade. Radial arms saws can be touchy to dial in perfectly.
Dave

 

[michaelgarner]

One thing you can do is push the radial arm saw rather than pull it. You can control the feed rate across the cut. I hope this helps you.

 

[NCPete]

didn't think you were supposed to push RAS's? it's ok with SCMS, but not RAS for some reason?

 

[Howard Acheson]

I have owned and still use a RAS for crosscutting. What you are seeing can be fixed with a complete alignment of your saw. Your instuction book will lead you through the process. Take it step by step as each step is dependent on the accurate completion of the prior step. Pay particular attention to the skew adjustments. It appears your blade is not absolutely parallel to the cutting line. That's different from the cut line being perpendicular to the fence. It's similar to the blade not being parallel to the miter slot on a tablesaw.

I'm sure your problems will be long gone with a good and careful alignment.

BTW, cherry and maple are two woods that contain lots of sugar. That's the reason they burn so easily. But a well set up saw, with sharp and proper blade, should not cause burning on either

 

[jaustin]

I will check my alignment again.
I must of misunderstand something when you use the radialarm saw.
when you use it i thought you where supposed to push the blade into the wood(away from you). Vs pulling the blade toward you.
Have i been using my saw wrong?

 

[DaveO]

Yes, you pull the blade to you. That action causes the wood to push against the fence. I don't think that it is very safe to push the blade towards the fence. That could be some of your burning problem.
Dave

 

[jeff...]

Got the moisture content of that cherry? Could be it's a little wet, that could cause the wood to burn also. Don't ask me how I know that :roll:.

 

[Howard Acheson]

>> i thought you where supposed to push the blade into the wood

Nope, pull it evenly without too much speed.

 

[Kyle]

I believe you will find your cutting feed rate is too slow. I use a radial arm a lot and the same thing happens if I feed my sawmill, molder and table top router. Cherry burns easily in fact all wood burns pretty easy especially the harder woods if the feed rate is off.

 

[McRabbet]

We had a discussion about push versus pull on RAS several months ago -- I am a strong proponent of the push cut for cross-cutting since it is not a climb cut. The blade is pushing the stock toward the fence and is cutting the same way a table saw cuts. The stock must be held down as there is a slight tendency for the stock to lift. With a pull cut, the teeth may grab as the blade tries to climb onto the stock. And, as we said the last time when this was discussed, I never rip cut on a RAS because I believe it is too dangerous (DAMHIKT). Was this cherry cut with a pull cut? If so, that may explain the burning (along with the other factors DaveO mentioned) -- you may have taken a slow pull to avoid grabbing -- my recommended faster cut is with a push cut with a sharp, trued blade.

Rob

 

[michaelgarner]

We had a discussion about push versus pull on RAS several months ago -- I am a strong proponent of the push cut for cross-cutting since it is not a climb cut. The blade is pushing the stock toward the fence and is cutting the same way a table saw cuts. The stock must be held down as there is a slight tendency for the stock to lift. With a pull cut, the teeth may grab as the blade tries to climb onto the stock. And, as we said the last time when this was discussed, I never rip cut on a RAS because I believe it is too dangerous (DAMHIKT). Was this cherry cut with a pull cut? If so, that may explain the burning (along with the other factors DaveO mentioned) -- you may have taken a slow pull to avoid grabbing -- my recommended faster cut is with a push cut with a sharp, trued blade.

Rob

I remember that discussion too, I am amazed at the level of knowledge we can collect together.

 

[jaustin]

Moisture content i do not know but i bought it kiln dried a year or two ago.I think it may of been even longer.It has been sitting in my building since then.

going to try and pull it instead of pushing.

 

[Ray Martin]

Not sur if I'm putting the pieces together correctly here but... if woods like cherry have a higher sugar content which makes them burn more easily and too much contact with the blade or blade out of align makes for more burn, does it follow that using a thin kerf blade can result in more burn?

Ray

 

[DaveO]

A thin kerf blade shouldn't result in any more incidents of burning than a full kerf blade in the same well tuned saw. A TK blade has thinner teeth and a thinner plate, than a FK.
Dave

 

[Travis Porter]

But a thin kerf blade can and will flex more than a full kerf blade.

Dave, you remember when you came by and my miter saw was not cutting right? I put a full kerf forrest in it and it has cut perfect since. I also changed my tablesaw a while back to full kerf and it makes a lot of difference in cherry (been cutting some up).