Chain Sharpening.. Acceptable discrepancy between teeth.

[wyk]

Dragging hard on the back stroke probably is - lightly is fine and also some old timers actually think it achieves a better edge.

 

 

 

Done right, it sharpens both the cutter and the file, and loosens debris from the file. In the end, it's not what a micrometer says, it's what the wood says.

 

[treequip]

Done right, it sharpens both the cutter and the file, and loosens debris from the file. In the end, it's not what a micrometer says, it's what the wood says.

 

 

How can that be the case? The cutters on the file face in one direction similar to those on a chainsaw or silky.

 

Rubbing them the wrong way is just going to damage the leading edge of the cutter, whatever it is.

 

How can the file become sharpened but the material of the cutter, the file is a magnitude harder than the cutter body.

 

They (used to) sharpen files by dipping them in acid.

 

Dragging a file back is the chainsaw equivalent of putting the chain on backwards.

 

In engineering if a file "pins" up (usually happens with softer materials) they use a wire brush to clear the debris, they certainly don't drag the file backwards over the work piece.

[peatff]

They use a file card brush to clean files, it has much shorter bristles than a wire brush. Files shouldn't be dragged backwards in contact with the metal you are filing at all as it blunts them eventually even though they are hard.

[spudulike]

From what I have seen in my workshop, some of the sharpening is laughable - mostly on home owner saws though.

 

Everyone knows you get the best edge with a grinder:lol: ...that's for Treequip to comment on - got to keep the old boy busy:001_rolleyes:

 

The angle of the cutters usually become more acute and pointed as it is easy to file the edge rather than the hook! A favourite of mine is a sharp chain and the raker depth gauges being to high so the chain polishes the wood!

 

If you are getting good chip out of the saw, all is good, personally I do it by eye and use a Stihl depth gauge for the rakers.

 

The grinder comes out for the mullered chains where filing would take forever...even with a new file and good technique! The cutters can always be lightly dressed after with a file as required!

 

People also forget that the bar is a supporting element to the chain, too much roll in the rails and it will allow only one set of cutters to work or even none of them in bad cases. I have seen many with one rail 0.5 - 1.0mm below the other:thumbdown:

[Woodworks]

How can that be the case? The cutters on the file face in one direction similar to those on a chainsaw or silky.

 

Rubbing them the wrong way is just going to damage the leading edge of the cutter, whatever it is.

 

How can the file become sharpened but the material of the cutter, the file is a magnitude harder than the cutter body.

 

They (used to) sharpen files by dipping them in acid.

 

Dragging a file back is the chainsaw equivalent of putting the chain on backwards.

 

In engineering if a file "pins" up (usually happens with softer materials) they use a wire brush to clear the debris, they certainly don't drag the file backwards over the work piece.

 

Could it be that drawing the file back gently the wrong way removes the burr?

 

Only use the file one way myself but might try it as an experiment.

 

Back to the original question I go for 0.2 mm variation. Check every 3 to 4 sharpens with a vernier gauge (cheap from Lidl)

[wyk]

How can that be the case? The cutters on the file face in one direction similar to those on a chainsaw or silky.

 

Rubbing them the wrong way is just going to damage the leading edge of the cutter, whatever it is.

 

How can the file become sharpened but the material of the cutter, the file is a magnitude harder than the cutter body.

 

They (used to) sharpen files by dipping them in acid.

 

Dragging a file back is the chainsaw equivalent of putting the chain on backwards.

 

In engineering if a file "pins" up (usually happens with softer materials) they use a wire brush to clear the debris, they certainly don't drag the file backwards over the work piece.

 

Theory is theory. I posted a video of what my chains do.

[wyk]

And if you get a bit creative with your chains, you can make one do this on a non ported 372 pulling a 28" bar in maple.

 

[treequip]

Theory is theory. I posted a video of what my chains do.

 

That's nice, do you have a video of your files?

 

Oh and its fact not theory

[wyk]

How can that be the case? The cutters on the file face in one direction similar to those on a chainsaw or silky.

 

The edge of the files face forwards, sort of like petals on some files. Once that edge is gone, the file stops sharpening. The edge starts to disappear rather quickly and they become replaced with a top plate. When you lightly scrape them the opposite way, you remove debris and help the edge face more forwards.

 

Rubbing them the wrong way is just going to damage the leading edge of the cutter, whatever it is.

 

It is just a light scrape as you pull the file back. In any case, this makes literally no sense at all. You sharpen knives by hand with the cutting edge facing the sharpening surface and square ground cutters are always sharpening by hand with the file entering the opposite way most use a round file. This knocks off the bur and leaves a very sharp edge. As you can easily see with my videos - especially the second one as you have likely never seen chips that large fly out of a mid-sized chainsaw with 3/8 chain. If you have, they were using a mild race chain.

 

How can the file become sharpened but the material of the cutter, the file is a magnitude harder than the cutter body.

 

An order of magnitude... Are we talking exponential? It depends on what the cutters are made of. We all know that files are usually W2 tool steel. Cutters are usually a closely guarded secret(as are drive links and straps), but any engineer can figure it out. Generally, cutters are high carbon steel. They do not need to be too shock resistant, and they do not need to be rust resistant as they are always oiled. This type of steel is usually hardened from 56-58hrc. W2 is about 62-65 HRC for files. I'm not sure if this qualifies as a 'magnitude'. What it means is they will both scratch each other's surface, but the W2 will last longer doing it.

 

In engineering if a file "pins" up (usually happens with softer materials) they use a wire brush to clear the debris, they certainly don't drag the file backwards over the work piece.

 

And neither do we. We brush it gently.

 

Again, theory is theory, practice is practice. If you don't like it, feel free to ignore us.

[bob]

If I am taking a lot off I use callipers but tbh if they all look the same size then that's usually close enough for me.

I always seem to end up re doing most other users chains to get them all looking the same.