Ripping chain sharping question

[tugmyroo]

Hello, I am wondering if anyone can help me with sharping my OREGON 75RD ripping chain. i have an OREGON file guide, the kind you clamp on your bar. my question is about the top plate angle i know it is 10 degrees but is it up the tooth or down the tooth? i dont know how to explain it. can someone send some pics on how they have there guide for the topplate setup please
Thanks

 

[BobL]

Try this - which one do you mean?

 

[tugmyroo]

PIC #1 Not to sure what side to set the top plat angle to



PIC #2 I set the angle to 10 degrees running down


PIC #3 I set the angle to 10 degrees running up the tooth


i know i am not the best at explaining my self

 

[BobL]

That adjustment you refer to in the photos is the "file guide angle" (see #5 in my picture)

It should be set at 10º with the high part of the angle at the cutter tip and the low part of the angle opposite the cutter tip.

The "top plate filing angle: is the other adjustment shown in your first photo.

 

[tugmyroo]

Okay okay that makes sense, thanks for the help. one more thing, how can one tell the proper depth of the file? Thanks again

 

[CTYank]

Okay okay that makes sense, thanks for the help. one more thing, how can one tell the proper depth of the file? Thanks again

For "normal" crosscutting, chain mfgs specify having 1/5 to 1/10 of the file diameter above the tooth. Easiest way I've found to check/set this is with a fingertip.
For milling, where most chain mfgs specify a lower grinder angle (more acute edge), you'd want the file a bit lower. How much? Anybody?

 

[BobL]

For "normal" crosscutting, chain mfgs specify having 1/5 to 1/10 of the file diameter above the tooth. Easiest way I've found to check/set this is with a fingertip.
For milling, where most chain mfgs specify a lower grinder angle (more acute edge), you'd want the file a bit lower. How much? Anybody?

File height above the tooth is what sets the hook or top plate cutting angle (TPCA see post #2 above).
The TPCA depends on the height of the file above the cutter and the size of the file/

When the file is high the hook angle is closer to 90º and results in a less aggressive cutter that does not go blunt as quickly and VV
When the TPCA is lower I say the cutter has more hook, meaning it's more aggressive and provided there is sufficient power the saw will self feed better but the cutters will not stay sharp for as long.

The size of the cutter "bite" and self feeding of the saw depends on a combo of the TPCA and at the raker angle

FWIW on regular 3/8 chain I use a 13/64" file in a 7/32" file guide. The result is that 23% (~1/5th) of the diameter of the file is above the cutter - helps keep the chain sharp in the hardwoods I cut.
However, you need to bear in mind that I'm using a smaller file, and 6.5º raker angles, which together result in a more aggressive cutter.