Chainsaw grinder questions, tips, tricks, and pics!!!!

[jeffkrib]

Thanks Philbert, yes I understand the file diameter controls the curve in the gullet. I keep my stone wheels the same radius as the file size.
If your swapping between grinding and filing this makes sense but if I'm grinding with a CBN wheel which gives a 1.5mm radius for all size chains are there any other considerations. Would the only down side be noticed when swapping between grinder and file?

With a smaller radius wheel the larger chains would have a straight line from the cutting edge before hitting the gullet as aposed to a curve immediately after the cutting edge.

Is the gullet similar to a chip breaker on a lathe or milling tool?

Chip breaker and how chip breaking happens - CNC turning - Cadem

Chip breaking not happening? Maybe you're using the wrong insert, with the wrong chip breaker geometry, or wrong feed rate. An explanation...

cadem.com

 

[jeffkrib]

Hopefully this picture makes more sense. Which would be the best grinding strategy left or right image.

 

[Philbert]

Is the gullet similar to a chip breaker on a lathe or milling tool?

I believe that the curved ‘C’ shape acts somewhat like a chip breaker.

My point was that a single pass of a file, or a grinding wheel, does not shape the entire gullet / cutter profile.

If you are happy with the radius at the top of the cutter, where the cutting occurs, you can back up the tooth and make additional clearing passes with that wheel.

That’s pretty much what I do with any grinding wheel, when sharpening.

But if the wheel is too thin, then it takes a lot of passes to get a satisfactory result.

Do you have a standard grinding wheel that you can profile to that diameter, and experiment with?

Philbert

 

[jeffkrib]

Thanks Philbert.

 

[Squish9]

Thanks @justoldsaws for organising a promo code.
I contacted Dinasaw regarding their ABN wheels, told them I'm grinding 3/8 low profile, .325 and 3/8. Asked what size wheel do they recommend? They have a wheel which grinding a 1.5mm radius or 2mm radius. They said the best compromise is the 1,5mm radius wheel. I checked my file sizes, the sizes are ,.
1/4 & 3/8 low pro: file dia 3.96 = 1.98mm radius
.325: file dia 4.76 = 2.38mm radius
3/8: file dia 5.55 = 2.78mm radius
Going by file sizes I would have thought the 2mm radius wheel would be better.
Question for the brains trust how important is the wheel radius and what exactly does it do?

I'm using one of their 4mm ABN wheels on 3/8 and 404. Knowing what I know now, I would have bought a 5mm wheel because it suits my sharpening style better.

I have not tried this wheel size in 325 or 3/8lp but can if you want to see what it does

 

[jeffkrib]

I'm using one of their 4mm ABN wheels on 3/8 and 404. Knowing what I know now, I would have bought a 5mm wheel because it suits my sharpening style better.

I have not tried this wheel size in 325 or 3/8lp but can if you want to see what it does

Thanks, if you can just get a bit of a feel for the smaller chains that would be good.

 

[Squish9]

Thanks, if you can just get a bit of a feel for the smaller chains that would be good.

325 husky and Oregon 91vxl 3/8lp

 

[jeffkrib]

325 husky and Oregon 91vxl 3/8lp

View attachment 437044View attachment 437045

Thanks @Squish9 much appreciated
To the eye the .325 looks about right, the 3/8 LP looks like wheel radius it too big.
I think I'll order the 3mm wheel.

 

[el33t]

I'm using one of their 4mm ABN wheels on 3/8 and 404. Knowing what I know now, I would have bought a 5mm wheel because it suits my sharpening style better.

Thicker wheels can probably be a problem with some chains, especially early in the chain's life when the distance between the tooth and the depth gauge is still small. The wheel can then interfere with the riders, especially with more head tilt.
And I think this is one of the reasons why often the recommended wheel thickness is smaller than the recommended file diameter for a given chain.
Here, it may also be that due to the relief angle, the tooth height decreases with successive sharpening, which may cause the thickness of the wheel to be too large at the end of the chain's life, as may also be the case with the file.

 

[president]

I believe that the curved ‘C’ shape acts somewhat like a chip breaker.

My point was that a single pass of a file, or a grinding wheel, does not shape the entire gullet / cutter profile.

If you are happy with the radius at the top of the cutter, where the cutting occurs, you can back up the tooth and make additional clearing passes with that wheel.

That’s pretty much what I do with any grinding wheel, when sharpening.

But if the wheel is too thin, then it takes a lot of passes to get a satisfactory result.

Do you have a standard grinding wheel that you can profile to that diameter, and experiment with?

Philbert

I do the same ,I use a 325 cbn onn 3/8th chain .First pass as usual then back off the tooth
and hit the gullet with second pass

 

[huskihl]

Hopefully this picture makes more sense. Which would be the best grinding strategy left or right image.

Sharpen with the rounded portion of the wheel, not the side of the wheel. You want a C, not a J. And then like philbert said, every 3-4 sharpenings back the tooth stop off a little bit and grind down so that the bottom is relatively flat all the way up to the raker

 

[Squish9]

I believe that the curved ‘C’ shape acts somewhat like a chip breaker.

My point was that a single pass of a file, or a grinding wheel, does not shape the entire gullet / cutter profile.

I don't think the C shape has any real benefit, It's just a shape that gets formed because of the shape of the sharpening tool. I run most semi chisel and all my square with a 85 degree side plate angle. You want just enough for the side plate to hit the wood square on when the cutter intially rocks back on impact.

It could be different in wood with different densities but, for the wood I cut, adding anymore side plate angle just reduces support of the corner. I don't see any improvement in cut speed by adding more angle.

It's worth playing around with to see what suits your wood, saw, bar length and cutting techniques. My experience has been the side plate has a much smaller effect than top plate cutting angle

 

[jeffkrib]

Thanks guys, I switched from filing to grinding probably 10 years ago. I've always dressed the wheel to the supplied radius gauge (assume its file size) which has worked for me. Needed this bit of education now the I'll have a fixed size radius. Nice and clear explanations guys!
Thanks again.

 

[huskihl]

I don't think the C shape has any real benefit, It's just a shape that gets formed because of the shape of the sharpening tool. I run most semi chisel and all my square with a 85 degree side plate angle. You want just enough for the side plate to hit the wood square on when the cutter intially rocks back on impact.

It could be different in wood with different densities but, for the wood I cut, adding anymore side plate angle just reduces support of the corner. I don't see any improvement in cut speed by adding more angle.

It's worth playing around with to see what suits your wood, saw, bar length and cutting techniques. My experience has been the side plate has a much smaller effect than top plate cutting angle

The C shape is just an instruction for symmetry, as opposed to grinding too deep looking like a J. If you always bury your grinder down to the top of the straps creating an angled J shape, the cutters will start to break off with 1/3 of the life left because there’s no meat holding them on down at the bottom.

As far as the vertical side plate angle making a difference or not, you might make a few test cuts and check the clock. More hook in the cutter (fitting more of the file below the cutter) creates a more acute angle on the top plate chisel and they will cut considerably faster than having a more vertical side plate. That upper side plate angle can be anywhere from 10° up to around 70°, as opposed to only changing the top plate angle from 20–35°.

 

[Philbert]

Not sure I agree.

Although, a ’square’ filed / ground side plate edge is more vertical, it is still sloped to ‘collect’ fhe grain as it passes through (crosscutting).

Same with the ‘C’.

As it passes through it ‘collects’ and cuts the grain on an angle, and scours the side wall of the kerf, severing any fibers pressed down with the lower part.

Anyway, it works.

Philbert

 

[Squish9]

The C shape is just an instruction for symmetry, as opposed to grinding too deep looking like a J. If you always bury your grinder down to the top of the straps creating an angled J shape, the cutters will start to break off with 1/3 of the life left because there’s no meat holding them on down at the bottom.

As far as the vertical side plate angle making a difference or not, you might make a few test cuts and check the clock. More hook in the cutter (fitting more of the file below the cutter) creates a more acute angle on the top plate chisel and they will cut considerably faster than having a more vertical side plate. That upper side plate angle can be anywhere from 10° up to around 70°, as opposed to only changing the top plate angle from 20–35°.

I can only speak for the dense hardwoods I cut but reducing side plate angle is a big help here. I had a post in a husky C83 thread here showing what happens filing it with a down angle and a reduced side plate. Changed from the original 30/45/45 factory grind to 30/75/55 and picked up a fair bit of cut speed

It will react differently in different wood types

 

[chipper1]

As far as the vertical side plate angle making a difference or not, you might make a few test cuts and check the clock. More hook in the cutter (fitting more of the file below the cutter) creates a more acute angle on the top plate chisel and they will cut considerably faster than having a more vertical side plate. That upper side plate angle can be anywhere from 10° up to around 70°, as opposed to only changing the top plate angle from 20–35°.

That's been my experience as well. I add a bit of side plate angle on semi-chisel chains to get them to cut a bit faster too. I find that adding too much side plate angle can make a chain very grabby, and that knocking the rakers down a bit is much safer/smoother. Regardless of which is done, if a chain is too grabby, I just take a couple swipes with a larger file and everything is good, then go back to the proper file size or wheel size the next time I sharpen.
I'm in communication with Elon about how to get the metal I removed that I shouldn't have to come back onto the cutters, bit we haven't figured it out yet .

 

[Philbert]

I'm in communication with Elon about how to get the metal I removed that I shouldn't have to come back onto the cutters, bit we haven't figured it out yet

Brazing? TIG welding? A dentist really good with crowns?

Philbert

 

[huskihl]

I can only speak for the dense hardwoods I cut but reducing side plate angle is a big help here. I had a post in a husky C83 thread here showing what happens filing it with a down angle and a reduced side plate. Changed from the original 30/45/45 factory grind to 30/75/55 and picked up a fair bit of cut speed

It will react differently in different wood types

Are you talking square chain? I was referring to round grinder angles

 

[el33t]

Not sure I agree.

Although, a ’square’ filed / ground side plate edge is more vertical, it is still sloped to ‘collect’ fhe grain as it passes through (crosscutting).

Same with the ‘C’.

As it passes through it ‘collects’ and cuts the grain on an angle, and scours the side wall of the kerf, severing any fibers pressed down with the lower part.

Anyway, it works.

Philbert

From the beginning of the introduction of grooving saw chains, which were initially sharpened with flat files, the recommended side plate angle was 90°.

Also, when chains sharpened with round files appeared, of which the Oregon chipper eventually captured the largest market, the required side plate angle was also 90°. Deviation from this value was considered a sharpening error.

Today's Oregon square ground (3/8) and chipper (.404) chains also have a recommended side plate angle of 90°. (85° for square filed .404 and 3/4 chipper for harvesters).

Many times you've probably seen the video (anyone have a printed brochure perhaps?), where Vallorbe recommends 90° for “hard” wood, and even 100° (backslope) for “special works”. It's a bit similar with circular saws, where the recommended hook angles range from -10° to more than 20° (ripping), depending on the material being cut and the direction of cut. The most versatile ones (general purpose/combination blades) have hook angles closer to 10°.