Oregon 73DPX chain Top-Plate Filing Angle, 30 or 35 degrees?

[John_Lincolnshire]

Took receipt of an Oregon 73DPX semi-chisel chain. The box the chain was supplied in stipulates a 30 degree top-plate filing angle. However, Oregon's 'Chains Maintenance & Safety Manual' depicts a 35 degree top-plate filing angle for that chain (see attached images).

I guess I'll simply file at the pre-ground angle on the chain. Just wondering why the anomaly?

Oregon Chains Maintenance & Safety Manual - 73DPX Chain Sharpening.pdf

[Brushcutter]

I've always done 30 degrees like it says on the box.if you put the guide on it out the box it's 30.

[peatff]

It will probably stay sharp a bit longer at 30°. I can't see 5° making much difference to the cutting speed.

[John_Lincolnshire]

Oregon have confirmed to me that the correct top-plate filing angle is 30°.

Thanks for the input guys.