Cutting Large Logs

Do you mean something like these?

https://www.youtube.com/watch?v=sKrxntwcXUI

https://www.youtube.com/watch?v=wofvIb2vooc

https://www.youtube.com/watch?v=HhIbmmPXfmg

Maybe you mean something like what they use for cutting stone?

Diamond Wire Saw Horizontal Cutting Setup

Yes,like that but with more aggressive cutting teeth.made for wood.

You need to contact the experts...

...no, not these guys...

More like these guys....

Not for felling trees,but for cutting logs to length.

I have seen the Japanese with a chain saw very with a very long bar,mounted on wheels,that can be manipulated easily,but it is still a bar-and-chain saw.

The really tough men were the ones that cut the giant redwoods before the chain saw.Axe and two man buck saw.They look like ants beside the sawed log.

https://duckduckgo.com/?q=old+lumber++jacks+standing+beside+cut+redwood+logs_image&t=newext&atb=v313-1&iax=images&ia=images&iai=http%3A%2F%2Fmedia.gettyimages.com%2Fillustrations%2Fgiant-redwood-tree-cut-down-for-lumber-in-california-1881-illustration-id821251424%3Fs%3D612x612

A bit like: this

But a continuous driven chain.

Exactly!Chain can be bought in rolls in nearly any length.

It sounds to me that what you are describing is a portable sawmill. They are available. They use a bandsaw type blade rather than a chain, but same principle. There are also smaller ones that you can clamp a chainsaw into, which use that for the sawing power and it provides the frame and mechanism. I'm pretty sure they can be used for both slices/slabs and boards. For example:

https://woodmizer.com/us/Portable-Sawmills

I have seen those,but there is a diameter limit on the wood miser type,and the Alaskan Sawmill type cannot be used to cut across,at least I have not seen it used in that manner.They are also very slow.

I am thinking something more portable for use in the field with no diameter limit except the chain length and HP of the motor.Even a PTO drive for instance.

What you are describing would be too unstable and dangerous...plus you would have to disconnect the chain to get it around the log = too time consuming....

What you are describing is impossible.

Chainsaw chains have their cutting teeth on the outer side of the chain and are guided by teeth on the inner side of the chain and those guide teeth are kept in line by a groove in the bar.

You are talking about inverting that chain so that the cutting teeth are on the inside of the chain loop but then what is on the outside of the chain loop to guide the chain?

Even if you did make a huge external bar to guide the chain, the chain would just fall out of the bar with no tensioning ability to keep the chain in the bar groove, such as done on a regular chainsaw.

And without a bar to guide the chain it would have no fixed direction guide, so it would veer off path.

And for what reason would you do all that?

There is no gain to be seen by the system you describe.

Consider the rope saw.The tension keeps it straight.

Insofar as varying the chain length,there are many ways to make a quick link system.A master link of sorts would enable connect-disconnect of the chain when required.

The length of the chain could also be varied by moving the drive motor closer or farther away from the log,depending on the log size.No need to adjust chain every time.

A variable speed drive,controlled by tension, could control the backward motion of the drive system.The motor speed would be controlled by a standard governor.

No need to man handle a large chain saw,simply loop the chain around the log,set the drive in position,and watch it cut.

This video shows one of these machines in action, notice how large and slow it is...

How your granite counter tops are made....

Stone is MUCH harder to cut than wood.

Every tool has parts to match the desired function

They have wheel a trencher made like that and you should see how fast it goes.

Much faster than the bar type,that looks like a large chain saw,which is slow by comparison.

They have giant ones for mining surface coal,called bucket wheel excavators.

The wheel type is not what I had in mind;Simply a long chainsaw chain,forming a loop around the log,with a drive mechanism at one end is what I was thinking.

Have you ever done any logging? What is the advantage of this proposed device? Faster? Cheaper?

I have done some logging,back in the old days when we used mules or oxen to drag the logs out of the woods.

The oxen team can out pull a mule team and are not as temperamental.

Whereas a mule would balk at a heavy load when it hit a hard spot,an ox would get down on his knees and keep pulling.

The intent is not for logging,but for cutting LARGE LOGS to length.

By large,I mean 8 ft diameter or larger

Not for felling trees,or trimming trees.

It is intended to be faster and cheaper,and require less man hours to accomplish the task of Cross Cutting large logs.It would be faster because it would have more cutting teeth in contact with the wood,a semicircle,vs a straight line.

Where may I ask, are you getting these 8' diameter logs?

https://www.parksconservancy.org/park-e-ventures-article/what-happens-when-massive-redwood-tree-falls

https://www.nps.gov/muwo/learn/photosmultimedia/index.htm

I agree. HTRN, where are you finding these 8' diameter trees that need cutting? Most of the lumber trees (and pulpwood too) that is cut in the US and Canada are 24" and under.

South America and Viet Nam,among others.

There are even some in N America.I have seen large oaks the would fit the bill.

debbie downer here… The kerf of a chainsaw type mill, is massive where there is a large amount of wood going as sawdust.

those types of mills are for hobbyists that’s looking for a economical way to stay busy. Remember, on those chain teeth on a chainsaw chain, you have a right tooth, gullet then a raker, left tooth, gullet then a raker etc…

where the tooth will cut, the gullet will collect the sawdust, and the raker will determined the depth of cut.

the rakers gauge the depth of cut on the chainsaw type cutter and the gullet is what’s taking away the sawdust. And those gullets are not that large, so cutting is going to take that much longer to cut through, and the longer the cut through a larger log, those gullets will load up and when those raker teeth gets filled, it will no longer cut.

Initially it may seem a easier way to bring a log down to a manageable size. But the time spend can only be justified as a hobby as well as a physical workout.

That’s my opinion…

So you would have to redesign the chain, maybe with a scoop that would throw the sawdust through the chain links outward...then you would need to design a way to grip the chain with the drive mechanism...then you would need a chain guard that would protect the user in case the chain snapped, could get ugly...

You may be on to something….
Throwing the sawdust outward, no,… that would pinch… but, throwing the sawdust through the chain behind where it already cut is a possibility and would help.
because the conventional chainsaws, you need to put in wedges as it’s sawing to pull the board being cut away from the cutting chain so it would be pinching the chain.

conventional sawblades both circular and band have a splitter behind the blade to keep the board being cut to keep85 from pinching the blade. When cutting, if the log has been cut for a while, where the ends dry out, there could be tension in the log itself where it’ll ‘squeeze’ the blade being cut.

don’t forget, that they also use water to lubricant the cutting chain as it’s cutting. A chain saw blade has a lot of moving parts…

The links will still be exiting the log,and dumping the dust at the same rate regardless of log size,if the chain speed is the same.

Most homeowner's chains are skip-tooth type with a blank link in between to lower the power requirement of the motor.

The automated tree cutters are not skip tooth,but have twice as many teeth per foot. This requires more power,but on a track-type tree cutter,this is no problem.

There are many chain shapes and configurations available for specific purposes.

Now this is what you want just use a longer bar;

https://www.youtube.com/watch?v=T5WO9nulOXc

I have used the rope pull chain type saw shown in a picture above quite extensively and it has some downfalls that I think would really work against a larger continuous loop version. On smaller branches they work fine but on larger stuff not as much.

For starters they are difficult to get the slot started, the small ones usually have a weight to orient the chain but that doesn't always work. Once you have a slot it does keep the blade oriented for the most part. Sometimes the chain will twist and get stuck in the slot and is really hard to get out. I am sure this would be more difficult the longer the chain.

Second and most problematic since the chain is wrapped around your log you are cutting almost all the way around. As you get into your cut the weight of the logs will pinch one side of the chain no matter what you do. This pinching force could easily be more than the strength of the chain. Perhaps if you can keep your log perfectly supported but that's not going to happen in the field. Even with the small ones I find it gets stuck a lot and I need a second person to spread the ropes so it is more like a band saw.

Last but the most important is safety when that chain snaps whom ever is operating that saw is likely to be very seriously injured or killed as the chain whips directly at them.

You do not apply constant pressure and direction to the cut when using the rope chain,and the direction is constantly reversed. Wedges are always used to prevent pinching.Guards are easily fabricated.

"Guards are easily fabricated."

There might be an argument for keep it simple here. Provide remote control, and, make absolutely certain that the area is clear before starting the saw.

I realise that some jurisdictions may not allow this.

A saw motor powerful enough to run a 30' chain would toss you around like a child, and the chain guard required would have to cover the operator completely...

I would just go with a large chain saw mounted on a tractor like this one...Let's face you are going to need some large machinery to manipulate logs this large...

Chainsaws became popular because of their cutting speed. And the control you have as long as the cutting teeth ARE moving in a -confined by the bar- mostly predictable trajectory. You lose either and there goes either speed i.e. usability, or safety. Most probably both. Using something similar to fall the tree is out of the question and I think this is obvious. Now cutting a fallen and fully (how?) supported tree it could work but with no real advantage compared to bar chainsaws unless it is fully remote operated from half a mile away for safety and with very (I meen very) tensioned chain to give anything resembling a straight cut, plus speed that would make it a beheading aparatus far far away if something went wrong e.g the chain split and fly away. Of course I don't doubt we can see it sometime somehow. Do I have to mention cases that science and technology has gone bananas? (LOL) S.M.

Let's try a little virtual logging ...