'Invention' of Square Ground Chain?

[CapitaineHaddoc]

I'm not looking to create some special chain that takes an hour to sharpen. I will try square ground, at the angles recommended by Madsen's and see if I can get the hang of sharpening it and if it works more efficiently for me. If not, I will go back to RS, which has always worked well for me. You can always play with angles and stuff if you want to make a short duration race chain. My objective is a fast working "work" chain. The big draw back of square grind seems to be whether you can get the hang of sharpening it properly. If you can, it is more efficient and smoother. If not, don't use it.

You're right to want to try! I did the same, and it's really something interesting to learn.
But beware, the files are expensive, and at the beginning you'll use a lot of chain.
In the end, I found it interesting, and it is true that the saw cuts a little faster. But for professional use, I do not find it interesting. The life of the chain is much shorter, and all thishas a cost that is not compensated by the additional work speed.

For work, i only use round ground chain, now. But sometimes i like to sharp and cut wit a square chain, just for fun!

 

[sachsmo]

Your English is a hellofalot better than my French


I say stick with what works for you.

Philbert has always been the type to 'over analize stuff eh?


After all we are just a bunch of knuckle draggers killing trees

 

[Terry Syd]

And guys that mod Wildthings...

 

[sachsmo]

Different breed we is.

 

[CapitaineHaddoc]

Your English is a hellofalot better than my French

Thank you very much! I had some vague notions, but since I frequent this website I am progressing pretty
fast!

After all we are just a bunch of knuckle draggers killing trees

Guilty!

 

[mdavlee]

The race chains will make a lot of cuts in clean soft wood. I have got 6 tanks in big oak bucking and noodling.

 

[Chris-PA]

You're right to want to try! I did the same, and it's really something interesting to learn.
But beware, the files are expensive, and at the beginning you'll use a lot of chain.
In the end, I found it interesting, and it is true that the saw cuts a little faster. But for professional use, I do not find it interesting. The life of the chain is much shorter, and all thishas a cost that is not compensated by the additional work speed.

For work, i only use round ground chain, now. But sometimes i like to sharp and cut wit a square chain, just for fun!

I agree - as I've said before semi chisel works best for my firewood cutting, but square ground was something I wanted to try. I cannot see the extra time and cost of files, etc. being worth the trouble for my use most of the time. However, if I'm felling something where I want speed it is nice to start off with a fresh fast chain, so now I can bring a saw with a loop of square ground on it. I can even touch it up in the woods if I need to and have a little more time.

Plus, I think these discussions and learning about different grinds helps to make one better at sharpening in general.

 

[Metals406]

The race chains will make a lot of cuts in clean soft wood. I have got 6 tanks in big oak bucking and noodling.

Yeah, you and I both know the longevity thing is a wives tale.

If you want speed, you use square hands down. If you want to cut sand or volcanic ash impregnated trees -- use semi.

No one chain profile is a do-all.

But if I'm in clean timber, keeping my tip outta the dirt, and not bucking skidded trees -- it's square all day long.

On forest fires, you're cutting so much carbon, a round profile makes a lot of sense.

 

[Philbert]

OK Metals, what is about square ground that makes it faster? Flat bevels? Bevel angles? Boxed corner? Forward side plate? other?

Philbert

 

[Metals406]

OK Metals, what is about square ground that makes it faster? Flat bevels? Bevel angles? Boxed corner? Forward side plate? other?

Philbert

Yes, it's the angles that make it cut faster. Imagine a chainsaw tooth like a wood chisel. A square profile makes a right angle.

Also bearing in mind what the working corner of a chain is the first to cut. Look at a square corner and look at a round corner. . . The answer is pretty intuitive.

 

[SierraWoodsman]

I didn't realize that Joseph Cox also Patented the square chisel geometry for a chainsaw cutter. Pretty amazing how studying wood boring insect larva mandibles revolutionized the forestry industry.
I also find it interesting how nature already perfected the most efficient wood cutter geometry. Different insects have different shaped mandibles perform a variety of tasks. Joseph Cox wisely chose to closely study the cutting equipment of the most efficient wood boring insect in the forest. If you study the 3-D geometry of the mandibles of the Ergates spic-ulatus (wood boring insect larva) The geometry at the point of first contact are strikingly similar to that of a chisel saw chain cutter with a clipped cutter heal. Observe the sketch of the of the side top cutting edges of the mandible. Wood-boring Beetle Mandible Geometry
Here's a magnified image of an adult pine boring beetle mandible also very efficient in boring through wood:



VS. a Leaf cutter ant Mandible with a single bevel serrated design much better adapted with thinner profile quickly cut through softer leaf material with greater speed:

 

[SierraWoodsman]

I like tweaking the grind angles a little to see what works best in different conditions.
My latest attempt on improving cutting speed are : honing the cutter after the initial grind (With green compound), clipping cutter heal.
Pictured .325" Carlton Chisel Converted round to square using Silvey R2/ rakers set @ .030" and gullets ground on HDG-6.
This process does seem to help a little. Hard to capture surface finish in the picture, but it's like a mirror after honing.
Might just be me, but I feel like edge durability is enhanced a bit by honing, but not sure why?
Haven't tried tunneling, rivet/raker thinning, stoning or tie-strap contour/polishing. I'm sure a lot further improvements can be made for speed.
but I'm happy with the results so far. Maybe 30% faster than of the roll round in the pine we tend to cut around here.
This is the chain that goes on the 346.

 

[Stihl 041S]

Honing would help hold an edge by putting a slight radius on the edge. Makes it stronger.

After sharpening drills I rum a Cratex along the edge.

Drilling in Duplex stainless with a 3" drill you need all the help you can.

 

[Philbert]

Ugly looking bugs. Nice looking tooth!

Philbert

 

[Terry Syd]

So, how do the bugs sharpen them cutters?

Got to thinkin' that Cox was pretty smart, but why didn't he copy the perpetual sharpening of the cutters, that's something I could really use.

 

[Philbert]

If you root around some of the patents (by Google, of course) you will see some patents for replaceable saw chain teeth. Kind of like the old 'injector' razors from the '60's and '70's.

The cutters wear more than the chains, so why not just replace the wear surfaces? They slid on/off with a dovetail shaped connection to the cutter body.

Oregon has been working on PowerSharp chain for years, but that is a different thread!

Philbert

 

[Philbert]

Okay, ran across this today . . . .

Someone tried to explain to me why full-chisel chain (not necessarily square-ground chain) cuts faster than semi-chisel chain.

I get the part about the sharper, leading point on full-chisel chain. But all other things being equal (top plate angle, cutting edge angles, depth gauge setting, etc.), he talked about cutting the wood grain/fibers once when cross-cutting, versus multiple times. It was not clear what he meant.

I ran across this illustration today, showing the full-chisel corner squaring out the bottom of the kerf on the initial pass, whereas, the rounded corner on semi-chisel chain leaves some of the fibers (outside of the corner radius), which get cut again on subsequent passes by the side plate cutting edge.



Since chopping/severing fibers takes a significant amount of force, additional cutting of some fibers contributes to a slower cutting speed.

Philbert

 

[MustangMike]

Great Post, That is why I love RS, and plan to try square file (RSLK). Just does not seem to make a lot of sense using a round file in a square corner.

 

[Philbert]

Just does not seem to make a lot of sense using a round file in a square corner.

Just to be clear - the illustration above applies to round or square ground/filed chain, as long as it is full-chisel chain. The advantages of square ground full-chisel chain over round ground full-chisel chain (as I think I understand it now) are due to the steeper top plate and side plate angles, along with the different shape of the point.

Philbert

 

[Chris-PA]

Okay, ran across this today . . . .

Someone tried to explain to me why full-chisel chain (not necessarily square-ground chain) cuts faster than semi-chisel chain.

I get the part about the sharper, leading point on full-chisel chain. But all other things being equal (top plate angle, cutting edge angles, depth gauge setting, etc.), he talked about cutting the wood grain/fibers once when cross-cutting, versus multiple times. It was not clear what he meant.

I ran across this illustration today, showing the full-chisel corner squaring out the bottom of the kerf on the initial pass, whereas, the rounded corner on semi-chisel chain leaves some of the fibers (outside of the corner radius), which get cut again on subsequent passes by the side plate cutting edge.

View attachment 337211

Since chopping/severing fibers takes a significant amount of force, additional cutting of some fibers contributes to a slower cutting speed.

Philbert

Ok, I don't buy that. The cutter is moving down in the illustration, so the fibers that are not cut are not so much the ones outside the corner radius, but rather the ones below. Therefore the same situation applies with the full chisel - there are fibers below that have not been cut yet.

EDIT: Clearly the cutter is moving towards the viewer, but as each cutter passes they move downward as the bar moves through the wood. So I don't see a difference in terms of fibers not cut between the two.