File size oddity?

[Stere]

Have a chainsaw witht the 90xp oregon chain and takes 4.5mm file 0.43

 

But noticed the wider kerf 91xp takes a 4.0mm file?  0.50

 

Seem odd a wider kerf chain needs a smaller file?

 

 

[Stubby]

Off hand I don't know the configuration of the two chains but if one of them has those " safety " links , you know the little bit that rides up before the raker then sometimes the larger file is a bit snug when you set at the correct angle .  At the end of the day both files will sharpen up ok if you can fit them in .

[Rough Hewn]

Is it the height of the tooth?
[emoji106]

[Stere]

Think you are right  it is the height  - makes sense. So the 0.43 chain is  taller than the 0.50.

 

0.50 being  low pro & 0.43 is tall.

 

 

 

 

 

 

[Wonky]

The size difference is , small in the files. 
The most important thing when sharpening a chain is the height of the file that’s above the tooth. (20%) 

the radius of the file dictates the angle of the cutting tooth.  Ie cuts a little quicker and dulls a bit quicker or the other way cuts a little slower & dulls slower.

you  can see from the chart/pics the difference is 75* or 80*  and 75* faster where as 80* sharper longer

this is a guide and your skills will mean you get slightly different angles on each tooth and thus the whole chain will behave differently. 

 

Those safety tie strap/shark fins play a part in the cutting characteristics as well. 
 

Also if you look at the std 3/8 Oregon & stihl chains, one says 5.5 & the other 5.2 in reality both work, and have the different cutting Characteristics as  I said above  it’s  the manufacturers recommendation.  

I have my preferences, as well as the depth gauge height 
when you get good at filing, then you will notice the difference  and more hook on the tooth means fast cutting and dulling

btw it took me a few yrs to know what’s  good & not.

 

Edited February 16, 2021 by Wonky
Better pic/file chain chart (readable)

[Wonky]

34 minutes ago, Stere said:

Think you are right  it is the height  - makes sense. So the 0.43 chain is  taller than the 0.50.

 

0.50 being  low pro & 0.43 is tall.

 

 

 

 

 

 

0.50 is 1.3mm dl and the 0.43 is 1.1mm dl 🧐.  
👍😉

[Wonky]

this vid, is my 461 with a 25 “ full chisel lpx Oregon. as you can see it cuts reasonably well  but a little to grabby at times  but this isn’t crosscutting,  we were just leveling off the log to put the ladder on before milling it.

 

 Std dogs on the saw 😉

 

[Stere]

yeah 1.1mm 1.3mm  dl are width.

 

But the 90PX is taller but narrower i think so is not really a   low pro chain if by low pro they mean height of chain above bar?

 

https://www.arboristsite.com/community/threads/0-043-vs-0-050-lo-pro-comparison.297662/

Quote

I will try to measure it later, but if I recall correctly the cutters on 90 are actually taller than on 91 - it's only really "lo pro" in that it has the same chassis geometry.

 

Edited February 16, 2021 by Stere

[Dan Maynard]

yeah 1.1mm 1.3mm  dl are width.
 
But the 90PX is taller but narrower i think so is not really a   low pro chain if by low pro they mean height of chain above bar?
 
https://www.arboristsite.com/community/threads/0-043-vs-0-050-lo-pro-comparison.297662/

I will try to measure it later, but if I recall correctly the cutters on 90 are actually taller than on 91 - it's only really "lo pro" in that it has the same chassis geometry.

 


Is that from Chainsawbars? Happen to notice I think the 22 is wrong as it's .325 pitch not 3/8 as that's the size for my 261.

[Stere]

Yeah