So, I found some time and analyzed the Carlton material (the chain manual containing the excerpts shown by PogoinTheWoods). What shall I say, Pandora´s box is opened I read all of it in the hope that it makes some things regarding raker depth clearer, I clearly failed. They mention many things that feel correct to me, many things that are out of question. But concerning important points they stay very vague, deliver misleading information and in my opinion even make mistakes, confuse some things, mix up some things. That´s my opinion; either they are on the wrong path sometimes, or I am too stupid to understand what they try to say. So into detail (once more ) : Carlton shows this image in order to explain how a chainsaw chain works. "As the cutter enters the wood, the leading edge starts to bite (#1) causing the cutter to rock back as far as the depth gauge will allow (#2) The cutter is now in the attack position. The cutter jumps off the guide bar and into the wood (#3). [...] The actual function of the depth gauge is to determine how far the cutter will rock back in position #2 and ultimately how large a bite the cutter will take. Also, it is normal fo the depth gauge to sink into the wood under certain conditions as illustrated in positions #2 and #3." So far the quote. When reading this and looking at the pictures, this all sounds plausible and right to me. But when you take a closer look and take Carlton by the word, it´s not so clear anymore to me. #1: Ok, the cutter sits on the rails, the chain is running, we move the saw to a piece of wood, the cutter´s leading edge touches the wood. #2: The leading edge pierces the wood a little bit, the cutter 'hangs', the chain moves further, so the raker side lifts up = the cutter rocks back. The end position after #2 is called 'attack position'. The raker sinks into the wood as well "under certain conditions". Questions to answer: How deep pierces the cutter? How deep pierces the raker? What are 'certain conditions'? #3: Ok, the chain moves further, the raker can´t pierce deeper anymore, the cutter can because it´s sharper than the raker. The raker was already in the air after #2, now the leading edge bites more and the cutter side lifts up as well, whole of the cutter jumps off. Questions to answer: How far jumps the cutter? Horizontally like in pic #3, more, less? I accept the principles they´re showing here and maybe they reflect reality. #1 - #2 - #3 is a black box though. We know that this all happens 'more or less' as shown, but we don´t know exactly. It surely depends on raker depth, sharpness of the cutter, chain speed, saw power and torque, chain tension, cutter shape, wood type,.... What´s my point: I don´t think we can quantify here anything. "All depends on everything..." Later on they mention 'guesswork', 'constant method' and 'progressive method' as methods for raker depth filing. They explain WHAT the constant method is, they say THAT this method is not recommended, but they really don´t explain WHY at this point (they say more or less it´s bad because it is constant). Then the same argumentation for the progressive method. They say "this means simply that the depth gauge setting changes with the length of the cutter", that this is recommended and the FOP can do this. Hope comes up, "it will be fully explained on the following pages". Now comes the excerpt given by PogoInTheWoods. And now things start to get really strange for me. They ride and ride upon the 'hinge point' thing. And try to explain THAT there is a problem with it, THAT the FOP takes care of this problem and HOW the FOP takes care of this problem. And as a consequence this all means that the FOP is a better raker depth tool than a constant one or eyeballing. Once again the illustrations: Look carefully! There obviously is something very wrong and not an unimportant one! So there´s the hinge point. Yes. Like shown above, the cutter rises up on the raker side, turning around the hinge point, which stays on the guide bar. Like in #2 above, they let the raker rise up exactly as high as the leading edge of the cutter, so that both points have the same height above the guide bar. Now look at the pics above: On the left side a new cutter, on the right side a more than half worn cutter. They claim both having a raker depth of 0.027". Fake news You can prove, that the two explained points have the same height on the right cutter. And you see that the left and right cutter have the same 'attack position'. That is not possible. When having the same raker depth and the same height for raker tip and cutter tip related to the guide bar, then the attack position on the right side would have to be lower than on the left side (more attack on left side). So how can this be? Very simple: Look at the right picture. Obviously the cutter on the right side has NOT the same raker depth than the one on the left side. It has a way lower raker, the one a progressive gauge like the FOP produces when the cutter is filed back. They argue against themselves at this point! Further down they say: "The theory behind the progressive method is, to increase the depth gauge setting as the cutter is filed back to compensate for the fact that as the leading edge crosses the hinge point of the rear rivet it will tip up less than when new and eventually will tip away from the wood". What a monster of a sentence... And clearly wrong in my opinion. It´s the other way round. The more depth gauge you allow (lower raker), the more the cutter can rise up, the more agressive is the 'attack position', the more the leading edge of the cutter gets more and more towards the hinge point. So towards the end of the chain´s life a 'decreasing' / left alone depth gauge setting would help to stay away from the critical 'hinge point', not an increasing one! What I think the truth is, and I don´t get it why they didn´t show it that way: "A progressive gauge maintains the 'attack position' during cutter wearing. A constant depth gauge leads to a 'attack position' with less and less attack during cutter wearing. Towards the end the progressive depth gauges lead to a slightly decreasing 'attack angle' by its design, which is desireable because of the 'hinge point' argument." Very interesting: Further down in the text, they show cutter #1, #2 and #3 in their normal position, they don´t compare the three ones in their corresponding attack position. You now know why, you would detect the fake. Strange approach, the hinge point thing. They didn´t use the true argument with the maintained attack angle and on the other side they tried to show the FOP´s strength dealing with the hinge point, but obviously it´s the other way round than they showed it. And BTW: I only showed now their wrong argumentation. Another problem is the hinge point concept itself. If this is really true, what does that mean? Clearly there is a usable part of the cutter towards the end of life point, that sits already behind the hinge point with zero attack position. And there is a part of the cutter near the hinge point, which goes behind the hinge point even when having only small attack. In their argumentation this now means that maybe the last quarter of the chain can´t be used, because the cutter tip goes behind the hinge point and tips away from the wood. I don´t think that this is the case in reality. Strange. In my opinion their manual has so much truth in it, many things are explained extra ordinary well. And especially regarding the rakers, they chose a very strange (and in my opinion wrong) argumentation, leaving out the real advantage of a progressive approach. I suspect the following: They wanted to show something that you can easy comprehend by a figurative manner. They chose the analogy of the 'see-saw' by purpose. So you can imagine something. In their explanations they only speak of 'depth', they never speak of 'angles'. Maybe they think that an angle is a more complex 'item' than a distance? My point here is not to bash Carlton. My point is, that we probably won´t be capable of quantifying something at this point. I have the feeling that we stay in the empirical corner here. It seems rather difficult to explain and quantify 'why EXACTLY' a constant cutting angle concept may be more appropriate and better working than a constant depth concept. Carlton at least couldn´t convince me That has to do with the pictures above #1 - #3, the black box. Too many variables. I don´t think that it is possible to find out more with my / our methods. Maybe complex computer simulations with many parameters and variables could help. And lab tests under controlled circumstances. I personally kicked in, like I said several times, at a certain point not questioning the past. For me a constant angle approach seems to fit and work in reality, so I personally aim for (rather) constant angles. I own a worn out chain on its limit, I filed down the rakers according to my gauge type 2, it works. And I never heard some of the 'real constant angles - DAF' party complaining about a chain not working because of the hinge point problem. Best quote of Carlton´s manual regarding rakers: "The most misunderstood part of a saw chain is the depth gauge". Yes. That was even proved by themselves.... So if even Carlton is not able to explain that stuff right, how could I ? So I stay by purpose with the 'my preference' approach. "I use method A because it works better for me than method B. I don´t fully understand why method A is better than B, but if it works better for me, maybe I don´t care that much about the 'why' ". Maybe someone of you can bring light into my darkness... As I said, maybe I simply misunderstand Carlton´s point here.