Some time ago I adjusted a few chains over to progressive using FOP. Although they always cut well I later found them to be rather grabby for plunge cutting. For plunge cutting do we need to maintain DG at .025" or less?
Do we need? That´s maybe not the right manner of asking this question.
I´ll try to answer the question indirectly:
On one side there are influencing parameters from the physical world, on the other side it´s a matter of personal preference.
So you are cutting hard or soft wood, normal wood in the summer and frozen wood during winter, you have a large powerful saw and a small weak saw, you use chisel or semi chisel chain, maybe we are talking about milling, you use a sharpening angle of 25° or 35°, you are sharpening the chain very frequently or rather rarely, you use normal chain or bumper/safety chain, you use normal profile or low profile chain, you use an electrical saw with low chain speed or a two stroke saw with high chain speed, you have different bars and tips, the application varies from bucking to felling to limbing and so on; that´s all that comes spontaneously to my mind, there may be definitely more parameters.
And then there´s your personal taste. How experienced are you with chainsaw work? What about your physical power, age, constitution? What is more important for you, working speed or safety?
That´s all part of the whole story.
One argument for my raker depth gauge approach is, that you can adjust it to your needs and preferences.
E.g. my two setups:
1. Forest work: 80% pine 15% spruce 5% hard wood. Stihl 034 Super, semi chisel chain 30°, no frozen wood, chain frequnetly sharpened, normal chain profile, all forest work with this one saw at the moment (maybe a smaller additional saw planned for limbing), we are talking about making personal firewood in a rather small self owned forest, the amount of wood is sufficient for 2 households during a year.
Principally most of these parameters speak for using large cutting angles.
On the other side I´m a beginner with chainsaw work, though feeling very comfortable with this beast of a machine, I try for the moment to stay a little bit on the safe side, so I´ll not make my saw overly aggressive.
I´m using my self-made rager gauge with cutting angles in the region of 6.5° - 7.0° for the moment. But I have already made my second raker depth gauge for this setup with cutting angles 8.0° - 8.5° for the near future
2. Home/garden work. Here I often use a small electrical chainsaw (less loud, no idling, there´s a power outlet in the garden). All sorts of wood. I use semi chisel low profile chain 30°. It´s an all purpose setup, my girlfriend uses this saw as well. In this use case safety is more in the foreground, speed not that important. So I use a chain with bumpers and a cutting angle in the 6.0° - 6.5° range.
Since plunge cutting is exercised we've dispensed with progressive DG...and everything is good again
I consider plunge cutting not as the 'normal' usage scenario. If you use that technique frequently then you maybe have chosen a bar or saw not that appropriate for this job
If you have rarely some larger trees, you can use a bar that´s maybe on the working limit of your saw. If you have that case more often maybe it´s time to buy a bigger saw with a longer bar.
Plunge cutting, in my opinion, is the exceptional case. You are already in the forest with your saw and a maybe little bit too short bar, and this one tree has to be felled now, for whatever reason. Then it´s time for the plunge cutting. But that´s the opinion of a hobbyist´s point of view and I know that pros use this technique more frequently.
I personally don´t like this technique very much. But I´m not a good reference at this point, I´m a beginner and so if I had the chance, I´d like to do all cuts with the bottom side of the bar
So I´d say at this point with the explanations above in mind: Use a raker depth that feels comfortable to you.
In the end it´s all about safety vs. speed. When using safety chain and very high rakers you are on the very safe side, but maybe the plunge cut is even not possible at that point ... On the other side you want to work very fast and make a very aggressive setup, but then maybe the saw starts to wobble around and the forces come free at the wrong place and you maybe get injured.
It all depends.
I personally avoid 'unsafer' techniques and when not possible I work slowly, concentrated and with high body tension and awareness level.
On the other side, when bucking straight clean soft wood trees on a plain and even field in the summer with a properly sharpened chain and a powerful saw, I see no reason for having rakers at all
File them down and lets go make some chips fly.---
