What angles are best for noodles?

[B_Turner]

Yeah that's one thing I noticed when noodling was getting the noodles out of the cut and off the chain catcher.I know one thing that worked was keeping the saw about 6" away from the log face so the noodles had a chance to drop off,but that means using a 24" bar on a 18" long log.A 346 with a 24" bar does look absurd.
DON

With a saw and sawyer that noodles well, pulling the saw back actually interferes with a greally good shaving stream.

With most setups people run it does help a little, though.

The chains and saw are the biggest factors, but having cut thousands of cubic feet of noodles doesn't hurt either.

 

[BobL]

Bob,

I have a great deal of respect for you and I know you have milled alot of wood and are alot smarter than I am.

Thanks Brad but I also know that you have held a chainsaw for many more hours than I have and your wood is almost certainly different. A lot of our wood is highly crossgrained and contains high levels of silica which has no grain preference so it doesn't matter what direction it's being cut.

I believe wood removal efficiency (energy wise) tends to be the fewers wood fibers cut per unit wood removed. Generally it equates to the largest shavings possible, although that of course can introduce certain inefficiencies depending on the machine that is doing the cutting (like a chainsaw which doesn't like too big a bite because the cutter rocks and eats up a lot of energy.) .

I'm still not quite sure why you think angled cutting, cuts through fewer fibers.

In this image, if the black line represents fibres, the angled cut (A) still has to cut the same number of fibres as the straight cut (B).

In case A the angled cut makes the fibres easier to cut but there is also more wood to be removed from the cut. The force needed to cut fibres relative to the 90º or straight across cutting force should reduce according a the cosine of the angle the bar makes with the wood. This means at 60º, 86% of the fibre cutting force is still needed while even at 45 degrees some 70% of the cutting force is still required. Counter balancing this reduced cutting force is a greater force needed to pull chips from the wood. The degree to which the gains and losses cancel each other out depends on the general hardness and nature of the wood. I'm guessing in your more straight grained softer woods, reducing the angle produces a noticeable gain in cutting speed. Next time I come across a softer log I will give it another go.

 

[B_Turner]

Thanks Brad but I also know that you have held a chainsaw for many more hours than I have and your wood is almost certainly different. A lot of our wood is highly crossgrained and contains high levels of silica which has no grain preference so it doesn't matter what direction it's being cut.



I'm still not quite sure why you thing angled cutting, cuts through fewer fibers.

In this image, if the black line represents fibres, the angled cut (A) still has to cut the same number of fibres as the straight cut (B).

In case A the angled cut makes the fibres easier to cut but there is also more wood to be removed from the cut. The force needed to cut fibres relative to the 90º or straight across cutting force should reduce according a the cosine of the angle the bar makes with the wood. This means at 60º, 86% of the fibre cutting force is still needed while even at 45 degrees some 70% of the cutting force is still required. Counter balancing this reduced cutting force is a greater force needed to pull chips from the wood. The degree to which the gains and losses cancel each other out depends on the general hardness and nature of the wood. I'm guessing in your more straight grained softer woods, reducing the angle produces a noticeable gain in cutting speed. Next time I come across a softer log I will give it another go.

Naturally the angle only really matters with wood with a definite grain direction. Crotches, some stumpwood and big burls for example can have crazy grain with no consistent grain direction. And maybe some of your guys' ill behaved woods.....


The angle and it's relative efficiency has to do with the concept of (our wood anyway both hard and soft) of wood as bundles of tubes which are sheathed in a cover of tough fibers. If a cutting edge were infinitely sharp then maybe it wouldn't matter the angle.

Think about all the effort that has gone into trying to design handplanes for thousands of years to deal well with cutting endgrain (like the end of a board). Contrast that with the ease of removing wood with a scrub plane (side grain).

Or the effort required to take a slice off the end of a pencil with a knife vs the amount of effort to cut it whittle style.

IMO anyway, Bill

 

[BobL]

Think about all the effort that has gone into trying to design handplanes for thousands of years to deal well with cutting endgrain (like the end of a board). Contrast that with the ease of removing wood with a scrub plane (side grain).

Or the effort required to take a slice off the end of a pencil with a knife vs the amount of effort to cut it whittle style.

Yep, I agree the angle the blade makes with fiber makes a big difference for chisels, knives and planes (BTW my real hobby is not milling but making woodworking tools so I have a fair idea how they work), but a CS is a very different beast compared to these tools.

If angle was the ultimate factor for a CS, why is is just as easy to for a CS to mill with the top plate cutters cutting with the grain, as against the grain?

Take a look at this picture,

Angle C has the cutters cutting with the gain like a knife sharpening a pencil. Angle A is against the grain - try sharpening a pencil like this and of course it's pretty hopeless - whereas a CS cuts just fine at this angle. Doing timed cuts I cannot tell the difference between A or B or C. Of course this is in my hardwood but I would be interested if you measure any differences between A or C.

The reason why a CS can cut in any grain direction so easily is because it is not really like plane or a chisel, with a single blade completely clear of wood except for the cutting edge. Except when noodling, a CS not a shaving action type tool but a bouncing multi-tooth chipping tool. When operating in milling or cross cut mode a CS is much closer to a hand saw or circular saw than either a plane or chisel - These rattle their way through cuts, partially cutting into and then tearing away fibers. They clearly makes chips, not shavings or curlies, and these have to clear the tight kerf so the saw can maintain a cutting action. A good example of why the latter is very important important is using too high a TPI blade to cut too thick a piece of wood. Comparisons between ripping and cross cutting hand saws and circular blades and cutting directions are also very interesting and may be worthy of a length fat chew.

Maybe it's just my wood, but any gains made by rotating the bar while milling appear to be offset by the fact that having a longer length of chain in the kerf increases chain/wood friction, and more sawdust has to clear the kerf. Most CS users also don't realize that even a razor sharp CS tears and chip as much as it cuts, which is why chainsaw accidents are so nasty.

 

[B_Turner]

I block and shape alot (a few hours a day lately) by hand (chainsaw of course) and I still very strongly feel that the angle does matter.

The extreme case is noodles, which with a sharp square chain tears fibers much less than cutting endgrain. Lift and separate. That's why the preferred method of cutting up a round is some variation of noodling.

But also when I am shaping or hollowing an object with a saw, I am very aware of the angle and direction I am cutting to the grain because of how much it matters both in terms of efficiency and surface left from the cutter.

Lately I have been hollowing some objects I call "tubes" and I often use the top of the bar instead of the bottom as the direction of the cut matters so much. One way is controlled and easy, the other is more a battle and leaves a fuzzy surface.

I don't see a fundamental difference between a multi cutter tool in this regard (e.g. chainsaw or table saw w/ ripping blades vs crosscut blades) and a handplane or chisel or a turning gouge. Sure there are differences in efficiencies, but the principles seem the same to me.

To me the angle and direction seem so clearly important (even in regard to cutter life), and the fact that someone of your brain horsepower feels so differently, is very surprising.

I'll have to think on it.....

 

[Gregford]

The theory behind higher top plate filing angles used for cross cutting is that it helps create a slightly wider kerf than lower angle top plates.

The reason that a slightly wider kerf is needed for cross cutting is because, of the three possible types of cuts, cross cutting is the one which leaves the ends of the wood fibres dangling in the cut. Chains, especially when blunt, tend to tear, rather than cut, a significant number of fibres, leaving short dangling fibres inside the cut. This reduces the sawdust clearing ability of a kerf and so can more easily jam the chain especially on really long bars. It also generates significantly greater side forces which increases wear on chain driver links and bar grooves.

End-on cutting and noodling leaves much fewer fibre ends hanging in the kerf. This means both forms of cutting can effectively use zero top plate filing angles as the fibres remaining in the wood are parallel with the surface. Sawdust can more dragged through the kerf and so is more easily cleared. When milling, higher top plate angles also creates a slightly rougher finish so any advantage of slightly wider kerf helping to clear sawdust is reduced.

So in theory, for noodling and milling instead of wasting power in creating a slightly wider kerf using a higher top plate angle it should be better to use a lower angle and direct the power to faster cutting. For most situations the gains will be very modest and un-noticeable to the average operator. Where I do notice the chain and bar wear effect is milling . If I use normal top plate chain I get much higher wear rates on the sides of chains and bar grooves than I do with lower angles.

But overall I agree with ST, it's not worth changing the chain just to noodle.

Now shall be start a raker height discussion?

Great info. I'm impressed.

 

[BobL]

Lately I have been hollowing some objects I call "tubes" and I often use the top of the bar instead of the bottom as the direction of the cut matters so much. One way is controlled and easy, the other is more a battle and leaves a fuzzy surface.

Yep - I can see why this is the case. But reduced control and fuzzy surfaces (ie more tearing) is one thing, but what about actual cutting speed?

I don't see a fundamental difference between a multi cutter tool in this regard (e.g. chainsaw or table saw w/ ripping blades vs crosscut blades) and a handplane or chisel or a turning gouge. Sure there are differences in efficiencies, but the principles seem the same to me.

To me the angle and direction seem so clearly important (even in regard to cutter life), and the fact that someone of your brain horsepower feels so differently, is very surprising.
I'll have to think on it.....

Because you shape wood from so many different angles with a CS, I have to defer to your experience especially in your wood. You have made me think about it a lot as well I'm now leaning back a bit towards some plane like action because I realized I have ignored the rakers and they restrict cutter edge depth penetration, unlike a circular or standard hand saw which do not have rakers. My experience is very much restricted by the wood I cut. I keep forgetting that some of our wood is so cross grained it is almost impossible to plane from any direction. My boundary between chips and talcum powder is very narrow and it makes me want to find a pine log and have a play around with one of my square ground chains.

All good fat chewing material.