File Sizes for Sharpening Chain

Arborist Forum

Help Support Arborist Forum:

Patrick1903

ArboristSite Operative
Joined
Dec 19, 2019
Messages
277
Reaction score
222
Location
VA
I found a 6 pack of 11/64 pferd files for $7.25 on Amazon, figured I’d try them on some 3/8 lp. Slightly oversized but I’ve heard of guys using 3/16 so it should work good. Anyone ever use this size file? I never knew it was an option.
Let us know how you like it for the LP. I’d be interested in doing the same.
 

Dudders

ArboristSite Member
Joined
Jun 29, 2019
Messages
61
Reaction score
208
Location
Sussex, UK
I have a Stihl Ms400 with a 20" bar, the chain is 3/8" RS3 size. I guess the recommended file size is 7/32. Will this always be the correct size even if i use chains from different manufacturers?
What would happen if I use a different size file, either too big or too small?
Plenty of answers there to your first question. I would answer the second this way, but must stress that this is only my opinion and the way I see it. I'm not a 'professional', just an average guy who's been sawing and sharpening his own gear for 40+ years - that doesn't mean my opinions are right, more that I'm set in my ways!

The new cutter has a gullet that is a perfect fit for the recommended file. A perfect fit is always a Good Thing - the gullet is an arc that neatly matches the right-sized file. If you use a bigger file - ie: with a wider diameter - it will make that arc shallower, or flatter. Use a smaller file and you'll dig into the gullet, making it more pronounced and rounder. A smaller file will also only work on the side (vertical) edge of the cutter and miss the top, horizontal edge. If the file is too big, it will only sharpen the top edge, not the side - at least, to start with, until it's totally changed the shape of the gullet.

If you use the recommended file, a small proportion of the file, at the top, will actually be above the level of the cutter. This means that the file won't just work on the side edge of the cutter, but also on the top edge, so sharpening both at the same time. If we apply absolutely no upward or downward pressure, but only put pressure horizontally into the cutter, then with the recommended file we should maintain the original gullet shape and also sharpen both cutting edges equally. We are all likely to work our files differently, however. Maybe without noticing it, we are pushing downwards, or lifting upwards as we file. Or we might have set our sharpening jig to hold the file too high or too low. The result, over several sharpenings, will be that the gullet will gradually change shape - if you tend to push down as you file, or the jig is set too low (not good), the gullet will take on a more pronounced shape, becoming deeper and rounder, as the file works its way under the cutter's top edge. You may also be filing into the chain links :eek:, but that's something else! If you file with an upward pressure, or the jig is set too high, the gullet will become shallower, or less pronounced. Either way, one day you'll notice that your gullets are looking wrong and some work may be needed to get them back as they should be. If your gullet has become too shallow and you go at it with a smaller file to deepen it, you'll only be sharpening the side edge, not the top, because the file is narrower than the gullet. Or use a bigger file when the gullet has become too pronounced, you'll only be getting at the top edge, not the side.

So that's what happens if you use a file that's too big or too small. I'd say to stick with the recommended size and use an even pressure, working the file horizontally into the cutter. If you notice after time that the gullet shape is too much this or that, then stay with the right-sized file but change your jig setting up or down, or pay more attention to the way you file and gradually get your cutters back to the way they should be.

As some others here do, I switch to a slightly narrower file once my cutters have been filed back to near the witness mark - partly because the top cutting edge gradually reduces in height towards the back, but also the drive-link of the chain is higher than the tie-strap and I'd rather not be filing into it.

Personally, I'm aware that if I don't pay attention, I'll be working the file downwards, so consciously have to counter that with a bit of upward lift. I also seem to apply more pressure when filing one side of the chain than the other, so end up with two different gullet shapes on the one chain... :oops:
 

HumBurner

ArboristSite Guru
AS Supporting Member
Joined
Dec 24, 2018
Messages
726
Reaction score
688
Location
SoHum
By mistake I sharpened a .326 chain with 13/64 Pferd (should be 3/16). Cut very good. BTW, that's a size up.

I do this on .325 that gets rocked and needs to be reprofiled.

You can either reprofile using the rec'd file, which will take many many strokes, or you can step up 1/64" and have to file significantly less. You will lose a small bit of metal/life, but is often worth the trade off. Don't forget the depths!
 

arborist

ArboristSite Operative
Joined
May 13, 2009
Messages
396
Reaction score
129
Location
Pinus strobus state. Home of the Peavey.
Plenty of answers there to your first question. I would answer the second this way, but must stress that this is only my opinion and the way I see it. I'm not a 'professional', just an average guy who's been sawing and sharpening his own gear for 40+ years - that doesn't mean my opinions are right, more that I'm set in my ways!

The new cutter has a gullet that is a perfect fit for the recommended file. A perfect fit is always a Good Thing - the gullet is an arc that neatly matches the right-sized file. If you use a bigger file - ie: with a wider diameter - it will make that arc shallower, or flatter. Use a smaller file and you'll dig into the gullet, making it more pronounced and rounder. A smaller file will also only work on the side (vertical) edge of the cutter and miss the top, horizontal edge. If the file is too big, it will only sharpen the top edge, not the side - at least, to start with, until it's totally changed the shape of the gullet.

If you use the recommended file, a small proportion of the file, at the top, will actually be above the level of the cutter. This means that the file won't just work on the side edge of the cutter, but also on the top edge, so sharpening both at the same time. If we apply absolutely no upward or downward pressure, but only put pressure horizontally into the cutter, then with the recommended file we should maintain the original gullet shape and also sharpen both cutting edges equally. We are all likely to work our files differently, however. Maybe without noticing it, we are pushing downwards, or lifting upwards as we file. Or we might have set our sharpening jig to hold the file too high or too low. The result, over several sharpenings, will be that the gullet will gradually change shape - if you tend to push down as you file, or the jig is set too low (not good), the gullet will take on a more pronounced shape, becoming deeper and rounder, as the file works its way under the cutter's top edge. You may also be filing into the chain links :eek:, but that's something else! If you file with an upward pressure, or the jig is set too high, the gullet will become shallower, or less pronounced. Either way, one day you'll notice that your gullets are looking wrong and some work may be needed to get them back as they should be. If your gullet has become too shallow and you go at it with a smaller file to deepen it, you'll only be sharpening the side edge, not the top, because the file is narrower than the gullet. Or use a bigger file when the gullet has become too pronounced, you'll only be getting at the top edge, not the side.

So that's what happens if you use a file that's too big or too small. I'd say to stick with the recommended size and use an even pressure, working the file horizontally into the cutter. If you notice after time that the gullet shape is too much this or that, then stay with the right-sized file but change your jig setting up or down, or pay more attention to the way you file and gradually get your cutters back to the way they should be.

As some others here do, I switch to a slightly narrower file once my cutters have been filed back to near the witness mark - partly because the top cutting edge gradually reduces in height towards the back, but also the drive-link of the chain is higher than the tie-strap and I'd rather not be filing into it.

Personally, I'm aware that if I don't pay attention, I'll be working the file downwards, so consciously have to counter that with a bit of upward lift. I also seem to apply more pressure when filing one side of the chain than the other, so end up with two different gullet shapes on the one chain... :oops:
Whats the difference in how the saw cuts between the two methods for you? Less vs more gullet, that is?
That last part is an issue that took me years to master lol! Now I watch very, very closely and keep both sides even. Cutting with a curve is never fun. Every so often, I'll still find myself bringing one side down a touch before she's get away from me. I'm sure we've all got to do the same. ;)
 
Joined
Jan 16, 2013
Messages
3,607
Reaction score
1,838
Location
North eastern Ct USA
I had a bunch of files some Stihl some hardware store and a roller guide for the Husky NK. the idea was to find a file that had the portion I liked higher than the top plate. I was at the time using Stihl NK chain. Got out the caliper and measured the part of the file that does the cutting and found I had a choice of 10 thousands of an inch between the choices. 1/64 converts to about 15 thousands. I think most of the files had both mm and fraction markings, but it is not real precise. Round file but some of the new chains have a more complex shape from the factory.

Something else I notice on the information sheet included in the Stihl chain package is the RS chains, the chisel ones call for angle b of 60 degrees and the RM ones call for angle b of 75 degrees. This angle is what the file height percentage above the top plate will affect. I have a Stihl clip (screw on bent wire) on type file guide but it does not say which angle it is supposed to produce. Same should follow for the 2 in one product. Probably a larger file in the guide for chisel if the called for 3/16 file makes the 75 degrees? Semi chisel stays sharp longer maybe this angle is some of that at least out of the box.

With the roller guide going bigger on the file gets back past damage to the top plate quite a few strokes earlier. Even if then going to the "proper" size after that it sure seems like less total strokes.
 

Dudders

ArboristSite Member
Joined
Jun 29, 2019
Messages
61
Reaction score
208
Location
Sussex, UK
Whats the difference in how the saw cuts between the two methods for you? Less vs more gullet, that is?
That last part is an issue that took me years to master lol! Now I watch very, very closely and keep both sides even. Cutting with a curve is never fun. Every so often, I'll still find myself bringing one side down a touch before she's get away from me. I'm sure we've all got to do the same. ;)
Can't say, really, because I've always tried to keep to the factory-set gullet, trusting that the guys making these things have done all the experimenting and worked out what's best. I would guess that a deep gullet produces a more aggressive (ie: sharper) top cutting edge, which would cut faster but go blunt quicker. A shallow one ought to be slower-cutting but hold its edge for longer. Others might know from practical experience, but I'll keep on with the original shape, as it's probably the happy compromise!
 

arborist

ArboristSite Operative
Joined
May 13, 2009
Messages
396
Reaction score
129
Location
Pinus strobus state. Home of the Peavey.
Can't say, really, because I've always tried to keep to the factory-set gullet, trusting that the guys making these things have done all the experimenting and worked out what's best. I would guess that a deep gullet produces a more aggressive (ie: sharper) top cutting edge, which would cut faster but go blunt quicker. A shallow one ought to be slower-cutting but hold its edge for longer. Others might know from practical experience, but I'll keep on with the original shape, as it's probably the happy compromise!
Oh I didn't expect that answer at all lol. It seems we're both set it our ways. This is why I laugh. I couldn't tell you why I prefer less curve to the gullet either, this is why I laugh. :D
Well, I'll confess, back when I used to use the correct size file, I do recall the increase I would get and I seem to recall, not liking that but for the life of me I don't recall why now. You've got me curious enough to try again to see what the story was. Back then, I didn't know better to ensure the top edge of the cutter was getting sharp, so I wonder if the larger file just made me lazy in getting things closer to correct. It's been, well, probably 18ish years since I've been reaching for an oversize file.
I learned this from the guy in the stihl shop. He was making me up a few chains and I asked what file size to grab with it and that's when he suggested, a lot of guys who come in, prefer the next file size up. I'd never remember now if he explained why that is, I don't think so. I come to understand after using them.

Perhaps and in all probability, I was filing incorrectly or simply not experienced enough with what all had to be done to ensure a sharp edge again. Had I known, perhaps I would have eventually preferred the correct size file as well. Now you've got me curious enough, I'll go ahead, of course these days with a much better understanding of what I'm doing with a file, than back then and try using the correct file size. Since it made a huge difference for the inexperienced me, I haven't even thought about trying one again today. Funny how we do things, figure out how they work and just stick with it without exploring new things. In my case, the "proper" thing lol. I'm gunna give it a go again and see what increased gullet does, as well as see if I can sharpen the entire cutter as quickly and weigh the pro's and cons. I'm still in my 40's. I'm not too old to learn new or in this case, old or proper tricks or methods, just yet lol. I better get to experimenting before I get much older though haha.
 

Okie

Addicted to ArboristSite
AS Supporting Member
Joined
Mar 7, 2015
Messages
1,879
Reaction score
1,502
Location
Oklahoma (USA)
Here is a handy gauge for around $6 to determine pitch, and get you into the ball park for determining chain sizes and possibly which file size to use. (when you see more than one saw chain size often)

OREGON Chainsaw (Chain Saw) Bar & Chain Pitch, Gauge, File Measuring Tool 556418
 

HumBurner

ArboristSite Guru
AS Supporting Member
Joined
Dec 24, 2018
Messages
726
Reaction score
688
Location
SoHum
It's been, well, probably 18ish years since I've been reaching for an oversize file.
I learned this from the guy in the stihl shop. He was making me up a few chains and I asked what file size to grab with it and that's when he suggested, a lot of guys who come in, prefer the next file size up. I'd never remember now if he explained why that is, I don't think so. I come to understand after using them.

Perhaps and in all probability, I was filing incorrectly or simply not experienced enough with what all had to be done to ensure a sharp edge again. Had I known, perhaps I would have eventually preferred the correct size file as well. Now you've got me curious enough, I'll go ahead, of course these days with a much better understanding of what I'm doing with a file, than back then and try using the correct file size. Since it made a huge difference for the inexperienced me, I haven't even thought about trying one again today. Funny how we do things, figure out how they work and just stick with it without exploring new things. In my case, the "proper" thing lol. I'm gunna give it a go again and see what increased gullet does, as well as see if I can sharpen the entire cutter as quickly and weigh the pro's and cons. I'm still in my 40's. I'm not too old to learn new or in this case, old or proper tricks or methods, just yet lol. I better get to experimenting before I get much older though haha.


Using an oversized file (1/64") eliminates the need to go back and hit the gullet. So a 1/4" file on a 7/32" rec'd tooth will clean and slightly open the gullet at the same time as filing the top plate.

There are a couple advantages to opening up the gullet, as opposed to keeping a flat gullet like stock. You get a slightly larger cutting radius of the side plate, as well as the potential for greater/increased chip clearance.

Depending on the bite you allow the chain to take (via depth gauge + hook), you can tailor a chain to a specific purpose (brushing, stumping, falling, firewood, etc.)

For brushing, I like a chain with minimal hook and a fairly aggressive depth setting. This allows a blip of the throttle to cut the brush quickly in a pass, helping to avoid rocks and dirt.

When you're sticking your chain in between rocks to get at a stem, you want to spend as few milliseconds there as possible.

This is also why I carry hand clippers in my back pocket and have loppers handy, much of the time. But not always.
 

pdqdl

Old enough to know better.
Staff member
Moderator
AS Supporting Member
Joined
Feb 26, 2008
Messages
21,913
Reaction score
48,856
Location
Kansas City
the maths say 14 / 64 would be 7/32. Though i am no expert. I have generally used stihl 13/64, though usually on oregon chain. 7/32 you kind of have to waller things out on that first sharpen.

And initially I thought it silly when i read post here about getting a smaller file as you got back to the witness mark, but I tried using a 3/16 on some mostly worn out (0.050, 3/8) chain and it made a difference in getting a nice shape of tooth.

That's an excellent idea. The profile of the tooth gets shorter as the length gets shorter. It makes a lot of sense to use a smaller file, too.
 

arborist

ArboristSite Operative
Joined
May 13, 2009
Messages
396
Reaction score
129
Location
Pinus strobus state. Home of the Peavey.
I watched a cool video on youtube last night. This good 'ol boy here, files just like I do. He's a hoot! A lot of fun to watch, even if you don't agree. He gets into using an oversize file also a bit in there.





The only differences I do, is I turn the saw around to file the other side, but that's neither right or wrong, just preference.
The other thing is, I think 'ol Buckin Billy, is probably taking off a bit more than he has to. When I think he's sharp, he still takes what I believe are another needless half a dozen or more passes. This isn't "wrong" either, I just think he's going through chains a bit sooner than he needs to be is all. When he goes on saying things "there she is" or "there she goes, right there, did you see that!" and things like that, that's where I think he's done and he has just as sharp a chain as he would if didn't continue to shave off more chain after that. It's kinda funny, he acknowledges he's got it but he keeps taking her down a lot more after.

Any rate, the way he files and the file size match what I do. I wish I had something like this to watch over 20 years ago! I learned the same things this good 'ol boy has through experience, no doubt, just as he did. Anyway, agree with his method or not, I thought you guys would get a kick out of watching that one. He's entertaining. Green horns should pay great attention! This video will no doubt help anyone with under 5 years cutting experience with a nice big boost in your filing ability!
Just one note for greenies, when he carries on and cleans up the chain, notice he keeps going a lot. Well, you can feel when you're done, after watching the chain clean up too. You'll feel the file slide and cut super smooth. That's how you'll know when taking more down will just remove good sharp chain and just make you go through chains faster, so I recommend stopping when you feel she's sharp. Watch though! You'll cut sharper after watching, if you're new. I've no doubt.
 

Iffykid

ArboristSite Operative
Joined
Sep 19, 2021
Messages
131
Reaction score
173
Location
Minnesota
Oh come on. Have a sense of humor. Life's way too short to take it too seriously. Man, if this guy was my neighbor, we'd hang out and we'd be cutting all the time. :)
Buckin was not to bad when he first started, now he just pumps out videos just to be putting something out and to listen to himself talking.
 

Papi3

ArboristSite Lurker
Joined
Sep 20, 2021
Messages
8
Reaction score
1
Location
west seneca ny
I have a very similar post, and to answer the OP's question. I have two exact size chains from Two different manufacturers and they call for different file sizes. the difference with my chains is 1/32 rather than 1/64. the manufacturers of the chains are Oregon and the other Stihl. Both have the same chisel tooth, and everything else is the same specs.
 

jackrabbit

ArboristSite Member
Joined
Feb 18, 2022
Messages
57
Reaction score
80
Location
Carpenter, WY
Would ut be easier if we use mm? 7/32=5,5 mm and 13/64=5,2mm. I know that most of you folks are from USA and that I am used to the metric system, but Quiet honest I think the metric is easier to understand, but maybe I am just simple minded.

There are two types of countries on this earth; those that use the metric system and those that have walked on the moon......
 

dennish

ArboristSite Member
Joined
Sep 11, 2008
Messages
91
Reaction score
64
Location
norcal
You are correct. Metric is easier and make more sense. But here in the USA there has been resistance to change to metric.
 
Top