Do chains ground with CBN wheels retain their sharpness longer?

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Mike Kunte

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Hey, Guys!
I have been grinding chains for a commercial sawyer for about 9 months. He drops off 30 chains at a time every 3 months or so. At first I struggled to get feedback from him regarding the performance of the chains (he cuts a mixture of wet and dry wood). Eventually I was able to get his take on things. According to him, his chains used to net him 1 1/2 to 2 loads (that's one pickup plus a trailer full) per chain. Currently, he is managing 5 - 6 loads per chain. That's around 3x as much cutting per chain!
Question: what, in your opinion, is causing the chains to last so much longer? The only variable I can see at the moment is the CBN wheels I am using on my chain grinder. I know most saw shops use the standard vitreous wheels. Could it be that the finer finish left by the CBN wheels makes for a longer-lasting cutting edge? It's much the same with knives - when the edge is stropped, it tends to last longer.
What are your thoughts?
Thanks.
Mike
 
Maybe, sorta, kinda, in theory. A rougher edge presents a varying amount of steel to the item being cut. In theory a more uniform edge will last longer because there are no "high spots" or tiny "leading edges" getting dulled first which would lead to heat and friction leading to more dulling. In practice I don't know if it really works considering the variety of conditions he'd face cutting a pile of wood.
 
I do not think there is a big difference between a good edge and a perfect edge other than you get cuts in your hand easier with the latter.
Like previous answer, the difference is in something different.
It might be different trees (that where not dragged through mud for instance) or a new employee that understands that changing chains takes more time than working more carefully.
 
I believe all those answers are part of it. Better wheel, setting the depth gauges properly, angles are more spot on, clean vs dirty wood, not driving the bar into the dirt as much, they're getting more efficient at cutting etc etc.
Either way, sounds like it's working out well for both parties
 
I can't speak to chains, but with knives it's not quite as simple as a smoother edge (assuming angles are the same) is better. I can attest that a belt sharpened knife cuts through cardboard better and for longer than a mirror polished edge. It's almost like a sawing tooth cut vs a straight razer "push" cut.

The mirror edges tend to cut tape better I think because you're gliding through the tape versus sawing back and forth. The mirror edges are easier to clean which also helps them stay sharp..

A chain is more of a "push" cut, so I would guess than a more polished sharpening face is going to last slightly longer... but I bet that it has way WAY more to do with angles than the edge finish.
 

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