Sharpening "down" angle?

[gstrom99]

I've always angled my file "down" the 10 degrees called for in the specs. I got a new 4.5mm Oregon file for my Dewalt battery saw. I actually read the directions yesterday and noticed it stated to run the file LEVEL @ 0 degrees. Which is correct, and what difference does it make?

 

[Eagle1]

Both depending on the chain. Full chisel chain is often 10 down, but semi chisel is usually flat. That are many types of chain and they are not sharpened the same way. Ripping Chain is 10 - 15 degree cutting angle vs the 30-35 degree for crosscut chains. The "experts" often set up cutting tooth geometry to their preference or application not the OEM spec.

 

[RandyT]

Both depending on the chain. Full chisel chain is often 10 down, but semi chisel is usually flat. That are many types of chain and they are not sharpened the same way. Ripping Chain is 10 - 15 degree cutting angle vs the 30-35 degree for crosscut chains. The "experts" often set up cutting tooth geometry to their preference or application not the OEM spec.

Just to build on this Some ripping chains are filed at 0 degrees meaning straight across. round ground full chisel is normally 25 degree top plate angle with 10 degree down angle. In comparison square ground is done with a file at 45 degree holding angle with a 45 degree down angle toward the outer edge of the tooth, which is reality creates a 20 degree top plate angle.

Semi chisel is normally 30 degrees but can be 35 for softer woods and 25 for hardwoods. Full chisel is normally 25 degrees, but can be 30 for softwoods, and 20 for hardwoods, which also correlates with the 20 degree top plate angle of the square ground chain.

 

[prs]

Even with round chisel I file level due to our local hard woods like oak, hickory, ash, and such. The 10 degree drop initially cuts faster, but the corner edge wears faster in hard woods, thus in working, the edge holds up better flat for me.