How I exactly sharpen chains

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Del_

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I’ve often wondered why a larger file wasn’t recommended, since you can’t get the top of the cutter and the gullet in a single pass with the proper one

The cutter changes height from the beginning to the end of it's life.

So a file would only be the perfect size to do what you've suggested at one part in the tooth's life.

Plus the fact that the recommended file size leaves the optimum radius under the top plate of the tooth.(we hope)
 

GoBigRed

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The cutter changes height from the beginning to the end of it's life.

So a file would only be the perfect size to do what you've suggested at one part in the tooth's life.

Plus the fact that the recommended file size leaves the optimum radius under the top plate of the tooth.(we hope)
Im not sure that is correct or maybe I’m reading it wrong. The height is a cutter does change. However, that’s why a gauge is used to bring your rakers down to ensure that cutter is consistently taking a chip of the same size thickness.
Sharpening, by its nature, will always change the top length of the cutter as you remove material to get your edge back. That doesn’t matter if it’s the recommended file size or one size larger.
The idea behind a larger file is to open the gullet and allow for those chips to clear out and keep the cutter “clean” and taking wood as is progresses through the cut. You can still open the gullet with the recommend file, but a larger file makes it slightly bigger and should keep it clean and taking wood until it clears the log.

I’m either way, I think for most folks their biggest problem is just keeping their damn chains sharpened and depth gauges adjusted. Without that, file size means nothing.
Great conversation gang. Love this forum. 👍🏻
 

davidwyby

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There is no one right way to sharpen. I mean I guess factory would be the closest thing as it’s average good for most things…but one can fine tune to preference for different desired performance or wood, or other situations. It’s fun to play with.

BBR is cutting big soft wood, big chips, clean the gullets for chip flow…I cut all kinds of stuff but a lot of super dried hardened eucalyptus (there is a thread about aussie wood here somewhere) and gullets are irrelevant…durability is more important.
 

Philbert

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The idea behind a larger file is to open the gullet and allow for those chips to clear out and keep the cutter “clean” and taking wood as is progresses through the cut
A larger diameter file changes the bevel angle of the cutter top plate, and the profile of the side plate.

If you just want a larger gullet, you can achieve that with additional file passes.

The gullet does not just pass / carry chips: it also functions as a chip breaker, when cross-cutting, to reduce clogging.
Philbert
 

Philbert

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This is a quick illustration of how the position and diameter of a round file affects the top plate cutting bevel angle (red line). Holding the file higher, or using a larger diameter file, widens this angle (more obtuse). Lowering the file, or using a smaller diameter, makes the angle narrow (more acute).

Some guys are only looking at the 'hook' or the gullet profile, but this edge is where half the cutting occurs (side plate edge does the other half). This angle makes a difference in the types of wood cut (hard, soft, green, dead, etc.), how fast the chain cuts, and how long an edge lasts. Different preferences for different applications. But you can still enlarge the gullet with separate passes, or different files, after sharpening this edge, just like you use a different file for the depth gauges, etc. Or, you can try using a larger diameter file, and holding it lower, to obtain a similar bevel angle.

The folks at STIHL, Oregon, etc. pick these angles / file diameters / positions for general use, based on their experience over 75 years. You don't have to follow their recommendations, but they are good starting points.

Philbert
File and Top Plate Bevel.png
 
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This is a quick illustration of how the position and diameter of a round file affects the top plate cutting bevel angle (red line). Holding the file higher, or using a larger diameter file, widens this angle (more obtuse). Lowering the file, or using a smaller diameter, makes the angle narrow (more acute).

Some guys are only looking at the 'hook' or the gullet profile, but this edge is where half the cutting occurs (side plate edge does the other half). This angle makes a difference in the types of wood cut (hard, soft, green, dead, etc.), how fast the chain cuts, and how long an edge lasts. Different preferences for different applications. But you can still enlarge the gullet with separate passes, or different files, after sharpening this edge, just like you use a different file for the depth gauges, etc. Or, you can try using a larger diameter file, and holding it lower, to obtain a similar bevel angle.

The folks at STIHL, Oregon, etc. pick these angles / file diameters / positions for general use, based on their experience over 75 years. You don't have to follow their recommendations, but they are good starting points.

Philbert
View attachment 942803
File depth is critical. If it's too low you have a needle like working corner that cuts great for a few passes, but becomes dull very quick. Even more pronounced in hard wood.
That's why I question whether using a 1/4" file to clean the gullet and sharpen the tooth at the same time works well.
 

davidwyby

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File depth is critical. If it's too low you have a needle like working corner that cuts great for a few passes, but becomes dull very quick. Even more pronounced in hard wood.
That's why I question whether using a 1/4" file to clean the gullet and sharpen the tooth at the same time works well.
The larger diameter does not leave too fragile a point.

Bout half way through he starts demonstrating file height effect.

 

rogue60

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The gullet plays no roll in the top and side plate doing their job above it.
Chips go straight back there is no curling of chips into the gullet. What breaks the chips is the reducing inward angle of the side plate, this angle pushes chips sideways (inward) and breaks them.
Softer timbers the chips can be longer as they have more give thus resisting breaking compared to harder timber that has less give and the chips break quite easily when being pushed sideways.
A hogged out gullet is good in softer timbers as it allows more room for chips from UPSTREAM.
That's the basics of it.


Technically speaking this is the only part of a cutter top and side plate doing any "cutting".
Screenshot_20211121-073611_Gallery.jpg
 

Hermio

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I won't claim to be an expert on this. But using the Pferd system (also sold by Stihl) with the 13/64 round file works well for me. It files the tooth and the raker at the same time, always keeping the 0.025" gap. This is on the Stihl R3 3/8" chain. It cuts faster than a new chain. According to Project Farm, it is the second best system to use for cutting speed. The best is the Granberg File-n-Joint. But the Granberg system is slow. I can file a 20" bar/chain combo in under 5 minutes with the Pferd system. Those skilled at freehand filing may do better, but I am satisfied with the results. I cust through seasoned white oak 12" rounds in under 5 seconds, and 18" red oak in under 10. The saw is the Stihl MS500i. My previous saw was a Stihl MS441C, which took about 50% more time.
 

Huskybill

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This is a quick illustration of how the position and diameter of a round file affects the top plate cutting bevel angle (red line). Holding the file higher, or using a larger diameter file, widens this angle (more obtuse). Lowering the file, or using a smaller diameter, makes the angle narrow (more acute).

Some guys are only looking at the 'hook' or the gullet profile, but this edge is where half the cutting occurs (side plate edge does the other half). This angle makes a difference in the types of wood cut (hard, soft, green, dead, etc.), how fast the chain cuts, and how long an edge lasts. Different preferences for different applications. But you can still enlarge the gullet with separate passes, or different files, after sharpening this edge, just like you use a different file for the depth gauges, etc. Or, you can try using a larger diameter file, and holding it lower, to obtain a similar bevel angle.

The folks at STIHL, Oregon, etc. pick these angles / file diameters / positions for general use, based on their experience over 75 years. You don't have to follow their recommendations, but they are good starting points.

Philbert
View attachment 942803
Then your not filing the gullet to the top of the link.
 

Hermio

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You can’t always trust the pferd style. View attachment 942817
I prefer the hooskie…can see what you’re doing and trains muscle memory for freehand. View attachment 942816
Well, as they say, different stokes for different folks. I have not used the hooskie. But I get a good hook with the Pferd system. But each Pferd unit is built for a specific file size. If you use the wrong unit, you will not get good results. The 13/64 size is optimum for the RS chain. RM chain requires a smaller file.
 

Huskybill

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What ever size file that will fit under the top cutting edge to the top of the links. Then use the file n guide to sharpen the top cutting edge.
 

Philbert

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The gullet plays no roll in the top and side plate doing their job above it.
Chips go straight back there is no curling of chips into the gullet. What breaks the chips is the reducing inward angle of the side plate, this angle pushes chips sideways (inward) and breaks them.

Illustration from Oregon. Shows the chip curling towards the bar, and to the side, on ‘hollow ground’ / round filed edges, where they break along grain lines. My understanding is that is why some guys get much longer chips with square filed / ground cutters.
9DCC0733-8DCB-455A-897C-6836B0012C4B.jpeg
Then your not filing the gullet to the top of the link.
Not sure what you are saying here. To the tie strap?

I try to maintain a smooth, continuous radius down to the level (‘floor’?) of the OEM gullets when sharpening.

Philbert
 

rogue60

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Illustration from Oregon. Shows the chip curling towards the bar, and to the side, on ‘hollow ground’ / filed edges, where they break along grain lines. My understanding is that is why some guys get much longer chips with square filed / ground cutters.
View attachment 942839

Not sure what you are saying here. To the tie strap?

I try to maintain a smooth, continuous radius down to the level (‘floor’?) of the OEM gullets.

Philbert
Yeah the chip goes rearward I was just making it clear it does not go down into the gullet or anywhere near the gullet for that matter. Also in a cut the chain is packed with chips not leaving the new forming chip any options apart from straight back.
Hardness and softness of timber plays a big a role in chip difference also. Same chain cut softwood and hardwood two different chips.
 

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