What's the most common MISTAKE newbies make while sharpening a chainsaw chain?

[pdqdl]

I'm not aware of a single person sharpening the cutters from their outer side to the inner.

Well what can I say? Now you have been informed. I routinely file front to back, inside to outside... Whichever is most convenient for where I am at and which saw & chain I am filing.

Now since this method has never come to your attention, here is the difference, and I will use your terminology. When you file from inside to outside, the file does not cut off the last tiny portions of the cutter, and it leaves a burr. ALWAYS. This tiny burr really isn't of much importance, and quickly comes off moments after you begin cutting the wood. The formation of a burr is more prominent when grinding with a wheel "from inside to outside". This will be the left side cutters if using an Oregon chain grinder with a one directional motor.

Now file "outside to inside" and you will find that the stroke is a bit more aggressive in removing the metal, it leaves no burr, and it also has a tendency to chatter if you don't hold the cutter better. Being a bit more aggressive while filing in that direction, you can work faster with less pressure, although you will still work harder with your off hand holding the chain better. It also leaves a sharper edge with no burrs.

Now you'll find thousands of folks to argue with me, but that that doesn't make 'em right. Perhaps this thread will introduce you to plenty of other folks that are "doing it backwards". Myself, I can't tell you what % of the entire world of chain filers adhere to your standard. Most, probably.

You quoted material from a sharpening website. Go back to how your razors, microtomes, or even pocket knives are sharpened: the sharpe edge is created by pushing into the stone with a slicing action. Doing it backwards still leaves a burr.

And if that isn't a convincing argument, just watch the rest of this video. Notice the filing direction.



Like I said: now you aware of at least a single person that does it that way.

BTW: I believe the reason all the chainsaw companies are telling you to stroke your file to the front of the bar is so that you are less likely to slip off the tooth, fly into the cutting edge and cut your hand to ribbons on the exposed cutting edges. It's a safety consideration more than it is a "how to get it sharp" issue.

 

[pdqdl]

...grind toward the cutter...

 

[KostasVolos]

The first reply ...





@pdqdl
Thank you for all the ( new to me ) info
you have showed me .
Really appreciated and an apology :
not really a well kept secret ,
but me that did not think out of the box .
Simple but great stuff there.

 

[HumBurner]

Most common is probably dragging the file in the wrong direction on the cutter (should file from the "inside" to the "outside" of the cutter), that or basically filing both directions like they're sawing a piece of wood.

I do file my depth gauges from both sides.......

 

[Natty Bumppo]

I use the Timberline sharpening jig. Unless one flips the jig around after doing half the teeth, you're sharpening 1/2 the teeth from inside to the outside, and the other half from the outside to inside. I've always been content with the results in the wood.

 

[HansFranz]

Go back to how your razors, microtomes, or even pocket knives are sharpened: the sharpe edge is created by pushing into the stone with a slicing action. Doing it backwards still leaves a burr.

You'll get a burr -- or "wire edge" -- no matter which direction you sharpen a knife or chisel on a stone. It's just what happens when two planes intersect...eventually the steel edge (wedge) gets so thin that it has no strength anymore, and it'll just roll over or break off. No way around it.

These might look like used lawnmower blades at this magnification, but I suspect they're scary sharp in real life:

On a chisel or carving tool, if you want the sharpest edge possible, you remove the wire edge burr with jeweller's rouge on a piece of leather or MDF (pulling the edge "backwards," BTW) ...I think Tom here does that when he sharpens his chains down to a 36000 grit size.

 

[pdqdl]

No way around it.

In general, I'd agree with that. Specifically, however, the harder the material being sharpened, the less likely it is to leave a burr. The coarser and softer the abrasive relative to the size and hardness of the cutting edge, the more likely you are to get a burr.

If you go with a fine enough abrasive, you will always get to the point where the size of the metal particles removed are smaller than the bending capacity of the metal being abraded. At that point, you get no burr, and you also get a very, very fine cutting edge. In most cases, the super fine abrasives aren't effective on anything until they are honing a very fine edge as well.

Try stropping that lawnmower blade for a while, and see how long it takes to get a keen edge. At least you'll not have any burrs.

As further evidence for "no burrs" being a possible outcome of sharpening, I dare you to show me a burr on one of my carbide stump grinder teeth. Carbide atoms are just too hard to roll out of position to remain attached to the base. They can wear off, but they don't form burrs.

 

[Philbert]

The biggest mistake ‘newbies’ make sharpening chain is expecting the file / jig / guide / grinder / etc., to ‘sharpen’ the chain.

The person sharpens the chain; the file (etc.) is just the tool that they use.

If they don’t know what a sharp cutter looks like (what they are trying to achieve), they may be ‘filing’ or ‘grinding’ the chain without sharpening it.

Philbert

 

[HansFranz]

If you go with a fine enough abrasive, you will always get to the point where the size of the metal particles removed are smaller than the bending capacity of the metal being abraded. At that point, you get no burr, and you also get a very, very fine cutting edge.

Any, and EVERY, time you sharpen steel where you have two planes intersecting in a wedge, you will ALWAYS end up with a wire edge "burr" eventually because when you have two planes intersecting in a wedge, eventually (right at the threshold of a steel thickness of zero) you will get a wedge of steel that is so thin that it effectively has zero strength. You can't sharpen a piece of steel to the point where you have one row of atoms of iron (and carbon and whatever else is alloyed in the steel) ... you can't even get CLOSE to that.

Long before you reach that point, you will be getting down to where the thin edge of the wedge is effectively the thickness of a single grain of steel (google "grain structure of steel") and where the steel will have almost zero stength. Once you reach this point, whatever is left on the "thin edge of the wedge" will effectively be a "wire edge burr." It will have no strength, and it will either fall off on its own, or break off at the lightest touch.

You won't be able to see this wire edge without a microscope and may not be able to feel it, but you will always get one. You cannot sharpen steel in any way where you have two planes intersecting in a wedge where the thickness of the edge will not eventually become smaller than the grain size of the steel. Once you reach that point, you will have a wire edge ("burr") that will break off, leaving a "truncated wedge" at the edge. And yes, this will happen on your carbide stump grinder cutters, or even ceramic or diamond cutters, simply because two planes intersecting in a wedge will eventually get infinitesimally thin...eventually the bonds between the atoms will become negligible (causing anything beyond that to have essentially no strength) ... and atoms ain't shaped like wedges.

Read up on steel metallurgy, the crystalline grain structure of steel, martensite, austenite, ferrite, etc., for more.

 

[pdqdl]

Cute, but I don't think this thread is prepared for atomic-scaled metalurgical considerations. As far as that goes, your picture with the burr shown was ground "away" from the cutting edge, not into it.

Having actually looked at a lot of very sharp cutting edges with a microscope, I can assure you that they can be sharpened without forming a burr of any sort. Perfectly smooth, without visible gouges? No.
Damned sharp with no burr whatsoever? Yes.

That final edge is put on with a finer abrasive than the grain of the metal. The burr is removed, the strong metal remains, and you got no burr whatsoever. Those of us that have ever used a straight razor know about this through the use of the leather strop.

Now with respect to chainsaw chains, let's just agree that filing towards the cutting edge leaves fewer burrs than filing away from the edge, and that the burr is worn away in the first 5 seconds in the wood, regardless of which direction you filed it.

 

[HumBurner]

The biggest mistake ‘newbies’ make sharpening chain is expecting the file / jig / guide / grinder / etc., to ‘sharpen’ the chain.

The person sharpens the chain; the file (etc.) is just the tool that they use.

If they don’t know what a sharp cutter looks like (what they are trying to achieve), they may be ‘filing’ or ‘grinding’ the chain without sharpening it.

Philbert

For years, this was one of those concepts I wasn't getting. I've never had steady hands, so filing did not come easy.

My goal, even though I use a file-n-joint, is to have my hands replicate the ideal stroke placement/pressure each time. I can feel when it is spot on, compared to good enough, compared to barely getting anywhere.

Another thing I find myself doing more is PULLING the file through the stroke with my hand near the working corner, instead of PUSHING with my hand opposite the working corner.

 

[jscb1bb1b]

Not cleaning off the grind stone as you move along from chain to chain and instead letting it build up with a black coating of filings than can settle all over the cutter's edge. It can set up a leading flair on the edge as well and make get red hot prematurely.

How do you dress a grinding wheel? Rounded and black is exactly what my wheel looks like.

 

[sean donato]

With the dressing stone that came with it. Little square shaped grey colored thing.

 

[jscb1bb1b]

Thank you for your response. I got the grinder used with no little gray thing or instructions. I also looked online for videos of dressing the stone with no help.

 

[pdqdl]

I got the grinder used with no little gray thing or instructions.

https://www.amazon.com/Oregon-DB-2-Dressing-Brick-Grinder/dp/B01HZPI3RE


Use the dressing brick to make the grinding shape correct, then keep using it to clean the grind wheel as needed. A dirty wheel makes a lot more heat when it grinds, so you either sharpen slower, or damage your chain by making it cherry hot and changing the temper of the steel.

This a really big no-no among professionals. It really ruins your day to get out on a job, only to discover that some numbskull hardened all the teeth with the grinder. Now your file just bounces off the chainsaw teeth, and it's nearly impossible to field sharpen by hand.

 

[user 189850]

With all the atom level discussions on sharpening, I thought I was back on BladeForums... =P

Biggest mistake I made for years was thinking the rakers didn't need to be sharpened. Then I bought a PFERD CS-X, and then the new mistake was thinking the rakers were being taken care of. Except they weren't because there wasn't ramp (which essentially turned into another cutter of sorts).

Reminds me of the story of the old guy who gets challenged by the young guy, to an axe cutting competition. The young guy can't figure out how he's losing, especially because every time the old guys cuts down a tree, he sits down and takes a break for 5-10 minutes. Ends up he was investing the time to "sharpening the axe".

 

[pdqdl]

That sure looks like a lot more than .030" depth guage clearance there. How are you setting the height of your depth guage teeth?

 

[HansFranz]

A dirty wheel makes a lot more heat when it grinds, so you either sharpen slower, or damage your chain by making it cherry hot and changing the temper of the steel.

This a really big no-no among professionals. It really ruins your day to get out on a job, only to discover that some numbskull hardened all the teeth with the grinder. Now your file just bounces off the chainsaw teeth, and it's nearly impossible to field sharpen by hand.

Interesting. I would have expected overheating the chain would make it softer, not harder. But I guess what happens is, it gets overheated, then it gets "quenched" either by the air or by the heat quickly moving into the cooler parts of the chain tooth, in effect re-quenching it. Which would mean that it would need to be raised to a certain particular temperature to re-temper it, reducing its hardness a bit...and that might be impossible to do if the teeth and the non-teeth links are of different tempered hardnesses...

 

[Philbert]

Thank you for your response. I got the grinder used with no little gray thing or instructions. I also looked online for videos of dressing the stone with no help.

Dressing the stone exposes fresh, sharp, abrasive, instead of rubbing dull grit against the cutter, heating it up.

Dressing stones for this use are usually coarse (24-40 grit) silicon carbide (‘Corundum’), and can sometimes found at hardware or farm stores.

https://www.ebay.com/itm/381951512049?hash=item58ee158df1:g:TY8AAOSwGrNZfgrY
Philbert

 

[Philbert]

Interesting. I would have expected overheating the chain would make it softer, not harder. But I guess what happens is, it gets overheated, then it gets "quenched" either by the air or by the heat quickly moving into the cooler parts of the chain tooth, in effect re-quenching it. Which would mean that it would need to be raised to a certain particular temperature to re-temper it, reducing its hardness a bit...and that might be impossible to do if the teeth and the non-teeth links are of different tempered hardnesses...

‘Air quenching’ is how I heard an Oregon engineer describe it. If it happens, you can usually grind through this layer, and restore the tooth so that it can be filed again.

Philbert