My brother got an electric chainsaw that uses Oregon 90PX chain (3/8" pitch, Narrow Kerf). We've been looking up the spec for the round file to use when sharpening, and are finding conflicting reports.
In one place, we found Oregon specs saying 4.5mm (= 0.177"), but in other places we're seeing 3/16" (0.187", probably close enough to 4.5mm to ignore the difference?). Both of these seem too big for the chain. We've found other places saying to use 5/32".
I thought that 91PX was the same cutter, just in a 0.050" gauge (as apposed to the 90PX 0.043" gauge). Everything we see for the 91PX says to use 5/32".
I have an email in to Oregon just to check if their literature saying 4.5mm is a typo, but don't expect to hear back from them for a while. If any of you use this chain, what size file are you using?
http://en.oregonproducts.com/pdfs/FilingAngles.pdf
Thanks, Lee. I found that, but it does not mention 90PX. Is it the same cutter as 90S or 90SG? I thought it was the same cutter as the 91PX.
I have no idea. I was looking for something else and saw this and thought it might help you.
I think a 3/16 would do fine. It would be 4.75 mm
Well, at least that makes 2 official Oregon places I've seen 4.5mm for something in the 90-series, so maybe it's not a typo. Baileys is one of the places saying 90PX uses a 5/32" file.
We'll try the 3/16 and see how it goes. It just seems big for such a small cutting tooth.
5/32 would be 4 mm. 3/16 is closer to 4.5 mm at 4.75 mm.
Quote from: LeeB on November 19, 2017, 10:04:55 AM
5/32 would be 4 mm. 3/16 is closer to 4.5 mm at 4.75 mm.
What I'm trying to figure out is why Oregon says 4.5mm for 90px, but 5/32 for 91px. I thought they were both the same cutters, just different gauge.
According to them the 90px has a 30°x 0° file angle and the 91px has a 30°× 10° angle. Looks the 90px just uses the 11/64 or 4.5mm file to compensate for the lack of 10°, just makes it easier for people to file who don't know how and so they don't file into the tie straps.
According to them the 90px has a 30°x 0° file angle and the 91px has a 30°× 10° angle. Looks the 90px just uses the 11/64 or 4.5mm file to compensate for the lack of 10°, just makes it easier for people to file who don't know how and so they don't file into the tie straps.
Just use your intuition. If it looks to big it probably is, so long as your not filing the links and the file is a bit higher than the tooth your filing ok, just my 3cents worth because 2cents dont buy much anymore these days.