Sawdust size while milling

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vientito

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My buddy used a brand new ripping chain today when ripping a spruce trunk. There was only one brief moment we saw chip sized sawdust spitting out and the rest are mostly dust like. We did notice at the end the chain was loose. Could that affect the size of the residue? A brand new chain i suppose is sharpened out of factory, hence that is not the reason. What could cause fine dust to spit out instead of chips?
 
When you are ripping you will get sawdust like from a skillsaw would produce ,but slightly larger ,but not chips like when cutting normal into the round ,the few times you got regular chips i bet you hit some knots ,even with a standard chain when milling/ripping you will get sawdust looking chips ,if got big chips you would have some real rough looking boards with a lot of torn fibers in them .Here is what my sawdust looks like milling cedar .
milling cedar 5-11-15 427.JPG
 
The rakers straight out of the factory is set up on the "wussy side" just in case someone puts it on a small saw.
In your softwoods you can use a lot lower rakers so start by drop the rakers by ~5"' try again, and keep doing that until the saw starts to think about bogging down.
Find out about 'progressive raker setting" and do it right every time.
 
My buddy used a brand new ripping chain today when ripping a spruce trunk. There was only one brief moment we saw chip sized sawdust spitting out and the rest are mostly dust like. We did notice at the end the chain was loose. Could that affect the size of the residue? A brand new chain i suppose is sharpened out of factory, hence that is not the reason. What could cause fine dust to spit out instead of chips?
I buy 100' reels & find touch up on the cutters needed along with setting the raker height for my preference. I found that .030" is too low on first slice (38" wide) and correct on the next 2 or 3. But that is in hardwood, spruce may be an easier cut than ash or oak. Bobl is the master trainer for sharpening chain, since he has had to face some of the hardest to cut wood (s) in the world down under. His experteez is freely shared here in milling.
 
I've found that few chains, as spun off the reel, don't benefit from filing up front. Some much more than others. And ... for milling notably more so than for crosscutting. You just can't get the cutters too sharp. Wussy depth gauges don't help either, disposing the chain to spit dustier stuff than chips. YMWV.
 
. . . . .You just can't get the cutters too sharp.

Unless it's chainsaw racing, where it's all over in seconds, it's pointless getting the cutters razor sharp. Unlike other wood working tools there's very little cutting by chainsaw chain, it's basically a "puncture and tear action". To assist maintaining this action, cutters are made by using a "softish" steel", that can be easily removed by filing , and the main wear surface is plated with a chrome hard plate. All filing does is remove the underlying steel to expose a new section of Cr plate which breaks off leaving a new hard edge. That edge is not razor sharp, in fact its pretty ragged compared to a fine wood working blade, a bit like a serrated bread knife. Due to its large grain size it is also quite difficult to make the Cr plate razor sharp.

The main job the Cr edge is not to cut but to survive high impact while being driven repeatedly into wood. If a chain is made razor sharp by honing (I know someone who does this to cut firewood :dumb2:) the very fine edge is lost in the first few seconds of the cut. Provided any glint (a sign that remnants of the old rounded over Cr edged is still present) is removed along the edges of cutters that's all that is worth bothering with for CS milling.
 
Unless it's chainsaw racing, where it's all over in seconds, it's pointless getting the cutters razor sharp. Unlike other wood working tools there's very little cutting by chainsaw chain, it's basically a "puncture and tear action". To assist maintaining this action, cutters are made by using a "softish" steel", that can be easily removed by filing , and the main wear surface is plated with a chrome hard plate. All filing does is remove the underlying steel to expose a new section of Cr plate which breaks off leaving a new hard edge. That edge is not razor sharp, in fact its pretty ragged compared to a fine wood working blade, a bit like a serrated bread knife. Due to its large grain size it is also quite difficult to make the Cr plate razor sharp.

The main job the Cr edge is not to cut but to survive high impact while being driven repeatedly into wood. If a chain is made razor sharp by honing (I know someone who does this to cut firewood :dumb2:) the very fine edge is lost in the first few seconds of the cut. Provided any glint (a sign that remnants of the old rounded over Cr edged is still present) is removed along the edges of cutters that's all that is worth bothering with for CS milling.
IIRC about 20% of file (round not square) is a good amount to have above crome. Sharpens while leaving enough steel below the chrome as a support for tearing chips off, if the depth guages are low enough to allow a bite the power head's torque can make with out bogging down.
A sharp ( small angle) edge is not supported & breaks away quickly. I may be saying what BobL said in a differing way, only because that has helped me to get a better comprehension.
 
I may be saying what BobL said in a differing way, only because that has helped me to get a better comprehension.

That's why writing something "in your own words" (as opposed to cutting and pasting) is a surer way of gauging understanding. I tried telling my students this but it didn't seem to work.
 
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