Saw chain sharpening critique wanted

Sharpening some chains tonight, and leaving the grinder at 60° (Northern Tool Oregon knockoff grinder) seems to leave too much hook, and chains dull quicker than I'd like. I went to 65° and it looks better, but still seems much.

Also, the pic of the unsharpened link, I believe this was a new Carlton A1C, sure doesn't look like hardly any angle at all. I have a new Carlton semi chisel that looks the same. What gives there?

I'm not a fan of the way the corner on the Carlton looks, not a crisp edge, but a small radius, what effect does this have on performance and staying sharp?

This is my first Carlton chisel, normally have Oregon, and a couple Stihl chains. I understand Woodland Pro is Carlton as well?

Here's a couple pics, not before/after, but 2 links next to each other, one sharpened one not.

Should have got some other views as well, maybe I'll go fire up the camera again.

Looks like it should cut pretty good just measure your raker depth, and take that down if needed.

BloodOnTheIce said:

Looks like it should cut pretty good just measure your raker depth, and take that down if needed.

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Yep; the raker needs a look at. The sharpened tooth looks good from this side.

Rakers haven't been done yet. I do them by hand after grinding.

Here's a couple other views of the sharpened tooth. Criticize away. Anyone else that wants to use this thread for a how's this chain look thread, feel free.

RS33 by zweitakt250, on Flickr


What dia. file are you using?

Steve NW WI said:

Rakers haven't been done yet. I do them by hand after grinding.

Here's a couple other views of the sharpened tooth. Criticize away. Anyone else that wants to use this thread for a how's this chain look thread, feel free.

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Looks good Steve. So does the raker from this angle.
I don't recall the setting on my Northern.

Maybe it's the lighting, but it looks like there is still a bit of a bevel on the top leading edge of the tooth.

In the first pic it's definitely noticable, not quite so much in the second.

It does look like there's maybe a bit much hook. I'd back the side plate angle off to 60 degrees, then not grind as deep. You can clean up the gullets later. There's no rule saying you have to do everything in one pass.

Maybe just a hair, too deep, really close, looks pretty dang decent, I know you mentioned you hadn't addressed the rakers yet, but get them down to where they need to be and you should be good to go. I've seen a helluva lot worse.

:msp_thumbsup: looks good as other have said go back to 60 degrees and lighten up on the depth a little... ihave ran 60/30/0 on about 10 chains and so far so good

Here's the only picture I can find. I can't get it to embed for some reason. It changed the view when making a post so it's not working right

http://www.arboristsite.com/attachments/chainsaw/169222d1295652827-042-jpg

Your working corner is really very narrow - too much hook angle. Likely to quickly snap in normal day to day use. People rate hook angle is being way more important than it is, so long as your hook isnt negative you're doing fine. Even is little as 5-10 degrees off vertical is enough to get good cutting going on.

If you think about the chain as being comprised of 2 'faces', the top plate and the side plate, and then each of those faces have an angle. Top plate angle and side plate angle (hook). Then each face also has a bevel. Most people understand top plate angle and side plate angle, and even understand top plate bevel... but very few people give any thought to side plate bevel which is the second most important thing on a chain after the working corner. Lets leave rakers out of the argument for a moment.

The working corner digs into fibres and lifts them up in a standard cross cut. The side plate then cuts them. Top plate bevel is important to some extent, but only up to a point. Generally steeper is better from the perspective of chain life. Too steep and the saw has to work hard to 'dig in', but for a working saw its better to err on the side of slightly too steep than slightly too shallow. Thats why when you look at standard file guides, they leave the file sitting fairly high in the gullet. Not very much top plate bevel at all, and only a small amount of hook.

When hand filing, top plate angle affects side plate bevel. A bit less top plate angle is probably a good thing, 25-30 degrees is good. No more than that needed. A 25 degree top plate gives you a 25 degree side bevel, assuming you are not using any drop on the file.

Things get a bit more complicated with machine sharpening! The radius on your wheel is what changes the side plate bevel, as well as how deep into the gullet you are grinding. When grinding, the radius of the wheel shouldn't go deeper than the top plate. If you do, you are effectively ending up with very little side plate bevel.

Imagine using a wheel with no radius, or if you have an un radius'ed wheel and an old chain try this out. Set your head angle at 65, and your vice angle at 90 so your top plate is square. You get plenty of top plate bevel, plenty of hook, but there is no side plate bevel at all. This chain will 'dig in', but with no side plate bevel the side plate actually has to rip the fibres out of the wood. Hard work for the saw! Now keep the same head angle and tilt the vice to 30 degrees. Look at the side plate angle... its getting some bevel. This will cut, but not great.

Now dress the wheel and go again with the same settings, but dont grind deep into the gullet. Only grind to the point where the dressed radius touches the top plate. Look carefully at the top side plate bevel, especially near the top... The top part of the side plate (the working corner) does most of the cutting. The top 1/8" is the most important part. The bottom of the side plate near the gullet will really never do any cutting. See how it has a nice curved side plate bevel? Take a cut and see how good it is (assuming your rakers are good).

Now keep all the settings the same, but grind all the way down into the gullet, the side of the wheel will be the part that is grinding on the top of the side plate now. This is fine on the top plate, but it ruins the top 1/8" of the side plate bevel. Compare it to the previous cutter. You'll see it clearly.

So what's the solution? Hand filing works good, because the shape of the file assures that so long as you've got the right angles, everything balances out. Grinding is trickier because each of the 4 critical geometries of the chain (top plate angle, side plate angle, side plate bevel and top plate bevel) can be altered by one or more settings on the machine, some of them fairly discrete. The way to go is keep your wheel dressed, and dont grind deep into the gullet. Clean your gullets out with a different wheel. Or just get back to hand filing ;-)

By the look of your cutter I'd say you are grinding too deep. It's hard to say without having a good look at the chain in person though.

Now for rakers, find BobL's thread on fileoplate. There's nothing I can add to that.

Shaun

Steve NW WI said:

Sharpening some chains tonight, and leaving the grinder at 60° (Northern Tool Oregon knockoff grinder) seems to leave too much hook, and chains dull quicker than I'd like. I went to 65° and it looks better, but still seems much.

Click to expand...

First off Steve, be careful believing that the angle is marked correctly on your NT grinder. They were not accurate on my Oregon 511A. Try to set a new chain in your vise and duplicate it, then read what your scales say. Do this for Right and Left vise rotation, and for head tilt.

Steve NW WI said:

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This photo looks like you are grinding deep into the gullet, rather than just shaping the hook on the cutter. I am assuming that you are using the right size wheel. Be sure to profile your wheel, and stop just as the radius of the wheel (tangent) hits the top plate. Go back and clear out the gullet later if you want to, but not on the sharpening pass

(From Oregon manual - this illustration actually shows it going a bit farther than it should)

Steve NW WI said:

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Hard to tell from the photos, but in this photo (first and last cutter) and the top photo (only cutter) it does not look like you have ground back the top plates far enough to get a clean edge. They look like they are radiused a bit (?).

Steve NW WI said:

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In this photo, the top edge of the cutter looks nice, but it looks like you did not get the side plate ground back far enough to have a clean edge.

But the proof is in the cutting - have you tried them in wood?

Philbert

imagineero said:

Things get a bit more complicated with machine sharpening! . . .

Hand filing works good, because the shape of the file assures that so long as you've got the right angles, everything balances out. Grinding is trickier because each of the 4 critical geometries of the chain (top plate angle, side plate angle, side plate bevel and top plate bevel) can be altered by one or more settings on the machine, . . .

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Shaun,

Our posts crossed, and you can see that we agreed on several points, except the parts quoted above. Everyone needs to find a sharpening method that works for them (even if it is taking the chain to a shop). But 'more complicated'? 'trickier'?

- The 'shape of the file' corresponds directly to the correct thickness of a properly dressed wheel. Wrong sized wheel, or undressed, corresponds to wrong size file.

- Grinding too low in the gullet corresponds directly to holding the file too low - too much hook and wrong top plate angle.

- Getting the 'right angles', and getting them consistently on each cutter is much easier with a grinder (once calibrated), as you dial them in. No variation, tooth to tooth, no wobbling in 2 axes, no variation in holding height across the tooth.

Chain grinders are not like chop saws; they require a little bit of education to set them up properly, but so does hand filing consistently.

Philbert

Thanks for the replies guys. Some pretty in depth stuff there Shaun, but I'm pretty sure I get what you're saying. (I work in metal fab, it helps sometimes...)

It sounds like I'm grinding too deep. Will someone explain why I'd need to clean up the gullets after sharpening (to the right depth)? To my way of thinking, they're just along for the ride by the time they contact wood, the cutting has been done above them. I know some on here are pretty anal about it, so it must serve some purpose.

I tried to take another pic of the top corner on this chain, but my camera is giving me fits right now, the lens in/out isn't working right. Maybe time to splurge on a DSLR.

Here's one from the wrong side cropped at full size, the one from the outside of the cutter I deleted already. Marked with the red line is about how far too deep I'm grinding? (Red line should line up with the top of the cutter if ground to the right depth?)



I do usually hand file with a Pferd Chain Sharp guide, but when they're trashed like this one, I use the grinder. I've only probably ground 30 chains on this thing, so I'm learning yet.

What I'd like, but can't find, would be some sort of diamond wheel dresser that keeps a good accurate radius, I have a bear of a time hand dressing a good radius on my stone.

Bear with me, I'm learnin...

Steve NW WI said:

It sounds like I'm grinding too deep. Will someone explain why I'd need to clean up the gullets after sharpening (to the right depth)?

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I think that it helps with chip clearance (?) Maybe having a smooth, continuous side plate edge yields a larger chip/curl? Besides, it looks funny if you don't.

Steve NW WI said:

Marked with the red line is about how far too deep I'm grinding? (Red line should line up with the top of the cutter if ground to the right depth?)

Click to expand...

Hard to tell from that side - I refer to the Oregon sketch.

Steve NW WI said:

I've only probably ground 30 chains on this thing, so I'm learning yet. What I'd like, but can't find, would be some sort of diamond wheel dresser that keeps a good accurate radius, I have a bear of a time hand dressing a good radius on my stone.

Click to expand...

Bottom line is, do they cut? You should be able to compare a cutter that you have hand filed with one that you have ground and get a very similar profile.

I do not know what the NT grinders come with. The Oregon came with a small Carborundum block and a plastic gauge. I touch the wheel up every chain or so. I use the Oregon or Molemab wheels - others may need it more or less. You could order the block and gauge from any Oregon dealer, but I am sure that you could improvise. The gauge just a piece of plastic that shows a half-round profile for each thickness of grinding wheel.

Philbert

Steve NW WI said:

Will someone explain why I'd need to clean up the gullets after sharpening (to the right depth)?

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In my opinion, the major reason to worry about gullets is subsequent grindings. You can end up with a saw-tooth within your cutters which can't do anything but cause drag. A clean gullet means you won't have to worry about inconsistent and parasitic losses to friction from that particular surface.

It doesn't hurt to grind a little too deep, doesn't change the cutting angles since they are ground with the straight side of the wheel.

I assume you are cutting hardwood, so I can't speak to what works best for that. But unless you are cutting locust or osage orange or similar, will guess your chains are getting dull due to dirt/rocks not due to way they are ground.

Rakers too high, otherwise your cutter looks decent to me.

Not sure about the "shadow," may just be dirt.

mtngun said:

Not sure about the "shadow," may just be dirt.

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? Was the photo taken after 5 P.M.? Did you use any Lectric Shave on your stone?

Steve NW WI said:

Thanks for the replies guys. Some pretty in depth stuff there Shaun, but I'm pretty sure I get what you're saying. (I work in metal fab, it helps sometimes...)

It sounds like I'm grinding too deep. Will someone explain why I'd need to clean up the gullets after sharpening (to the right depth)? To my way of thinking, they're just along for the ride by the time they contact wood, the cutting has been done above them. I know some on here are pretty anal about it, so it must serve some purpose.

I tried to take another pic of the top corner on this chain, but my camera is giving me fits right now, the lens in/out isn't working right. Maybe time to splurge on a DSLR.

Here's one from the wrong side cropped at full size, the one from the outside of the cutter I deleted already. Marked with the red line is about how far too deep I'm grinding? (Red line should line up with the top of the cutter if ground to the right depth?)

I do usually hand file with a Pferd Chain Sharp guide, but when they're trashed like this one, I use the grinder. I've only probably ground 30 chains on this thing, so I'm learning yet.

What I'd like, but can't find, would be some sort of diamond wheel dresser that keeps a good accurate radius, I have a bear of a time hand dressing a good radius on my stone.

Bear with me, I'm learnin...

Click to expand...

You probably don't need it with the volume you're doing, but you could switch to a CBN coated cyclone type wheel. They're good for well over a thousand uses, help you avoid overheating the cutters, and never need dressing. But you do pay for the privilege.