My biggest tree to tackle yet - monster white oak

[Yellowbeard]

Smaller chain won't make a lot of difference, 3/8 and 404 have almost the sam kerf width.
Lo pro is significantly narrower but you need a special drive sprocket and it will stretch too far on a long bar.
3-4 tanks sounds like a lot - I would have thought you could do those cuts in no more than 2 tanks.
Have we done a chain diagnosis for you yet? If not post some squarely side pics a cutter or two.

You haven't ever, but I would love advice. I finally feel like I am starting to understand the chain a bit and am learning how to sharpen it but now know enough to know that I have a lot to learn, so any and all advice is welcome. I took some pictures of it just as is. This is what it looks like after the last time I cut with it, thought I had sharpened it just before making the cut.

Please tell me what I am doing wrong (no doubt a long list). I have definitely come to agree that the most important things one can do are to have a very sharp chain and make sure one's air filter is clean. It's surprising how much difference just those two things can make. Would take advice on air filters as well, btw, but let's do chains first.

 

[Yellowbeard]

I have worried that I have my rakers too low. Just FYI: I generally sharpen by hand with no guide with a round file. Been thinking I may need to invest in a bench sharpener but I'm not totally certain where I would put it. I don't feel like the saw "self feeds" in the way BobL often describes, but I'm also not certain what that should feel like over 50+ inches of white oak.

 

[BobL]

OK - I just checked out your cutters and rakers on the first photo.
That's because it's the photo where the cutters are closest to the middle of the photo which makes the angle measurements more accurate to determine from photos than when the cutters are too high or low in the shot.

My first comment is you don't have enough hook or top plate cutting angle. Have read of the CSM 101 sticky - post 106 for what that means
Compare your cutters with these ones (Mine [bottom) and Will Malloff's [TOP])


You can achieve a greater hook just by going to a slightly smaller file or (if you use a file guide) putting the same file you use in slightly larger file guide.

Now the raker angles.
I measured and calculated 3 rakers in photoshop.
This is the angle I mean by raker angle
The calculated on this cutter is 4.3º, I measure 2 others and got 4.1º and 4.65.
This about normal for a standard raker gauge
The nominal raker angle to start with is at least 6º


In pine with a big saw you might want to think about running 7º or more, you just have try it out and see what works.
Mntgun was running 9º on small pine logs with a 660 at altitude.
I run 6.5º with the 42" bar in hard hardwood with the 880, and 7.5º using Lopro with the 441, and 25" bar.

Higher angles mean the chain will be grabby and cause more vibe and B&C wear and tear but it will cut like a (as we say here) shower of $hi7!

If you haven't got an DAF (Digital angle finder) to measure the raker angle use a micrometer to measure gullet width to raker depth ratios.
A raker gap that is 1/10th of the gullet width gives about a 6º raker angle.

Now we'll get into the last few % of speed.

1) Notice how my gullets are fully cleaned out, this helps to clear sawdust and can be significant on a wide cut

2) Notice the steeper angle of my raker top, and also how Will's is not steep.
My rakers are wide so I put a steeper angle on them. If the rakers are narrow it's not as important.
Raker top angles (not the same as Raker Angle - see above) contribute to the extent of cutter bite.
It might not appear so but rakers actually slightly penetrate the wood allowing the cutter edge to tilt more and thus to penetrate more wood and take a bigger chip out.
It's the subtle combo of raker angle, hook, and raker top angle that makes a saw self feed although there won't be much self feeding in 50" wide cuts.

3) You have a lot of resin on the chain. I would run more aux oil. Pine resin is a mongrel (that's why I rarely cut pine) but consider having a pump pack of diesel on hand and squirt that on the chain. 3/4 bar oil and 1/4 diesel is another alternative.

After all that you probably think, he has really studied this in detail and that I'm some kind of anal retentive nerd but that's just my science training coming out.

Hope that helps.

 

[BobL]

I have worried that I have my rakers too low.

You know your rakers are too low if the chain bogs down in the cut.
My dad was a timber faller and never measured a thing on his chains, he just used to file the rakers down over successive sharpening until the chain started grabbing - then he took 3 solid swipes at each cutter and that was his setting.
He passed away before I got into all the CSM stuff. I'm sure if he was around he would be laughing his head off to know that he had slaved his guts out to send me to College and then I turn around and play with chainsaws on the weekends!

Filters.
I don't mess about much with filters mainly because I cut mostly green wood and the high raker angles make more chips and less fine dust. When milling green wood I just knock the filter out every couple of hours , In dry wood a bit more often.

 

[Yellowbeard]

OK - I just checked out your cutters and rakers on the first photo.
That's because it's the photo where the cutters are closest to the middle of the photo which makes the angle measurements more accurate to determine from photos than when the cutters are too high or low in the shot.

My first comment is you don't have enough hook or top plate cutting angle. Have read of the CSM 101 sticky - post 106 for what that means
Compare your cutters with these ones (Mine [bottom) and Will Malloff's [TOP])

View attachment 530997
You can achieve a greater hook just by going to a slightly smaller file or (if you use a file guide) putting the same file you use in slightly larger file guide.

Now the raker angles.
I measured and calculated 3 rakers in photoshop.
This is the angle I mean by raker angle
The calculated on this cutter is 4.3º, I measure 2 others and got 4.1º and 4.65.
This about normal for a standard raker gauge
The nominal raker angle to start with is at least 6º

View attachment 530998
In pine with a big saw you might want to think about running 7º or more, you just have try it out and see what works.
Mntgun was running 9º on small pine logs with a 660 at altitude.
I run 6.5º with the 42" bar in hard hardwood with the 880, and 7.5º using Lopro with the 441, and 25" bar.

Higher angles mean the chain will be grabby and cause more vibe and B&C wear and tear but it will cut like a (as we say here) shower of $hi7!

If you haven't got an DAF (Digital angle finder) to measure the raker angle use a micrometer to measure gullet width to raker depth ratios.
A raker gap that is 1/10th of the gullet width gives about a 6º raker angle.

Now we'll get into the last few % of speed.


Hope that helps.

I see immediately what you mean regarding hook or top plate cutting angle (I think) and (I think) I understand why this matters (it's the same reason having longer fingernails work better for opening pull-tabs and for scratching). I have been using a .404 file to do my filing and see why you would say I could use a smaller file to get more hook. However, could I also achieve more hook simply by changing the angle at which I file a bit? Turning the file out of parallel with the TPFA and a bit deeper into the side cutter should result on more of a "belly" such as you and Will have in your profiles. Would that work? The problem I foresee with that is that it might tend to reduce the cutting effectiveness of the side cutting portions themselves. Thoughts? I don't mind just getting a smaller file, but what size do you recommend that I get in that case?

As for my rakers: It sounds like my cutting angle is close, if I am reading that right, to "normal" but not nearly big enough for what I am doing. So I am getting I need to set my rakers quite a bit lower. Correct? I guess I need to find a digital angle finder and get one to help. Do you recommend a particular one? However, I am a bit worried about the cutting part that the raker itself should be doing based on what you said. I usually file straight across the tops of my rakers, leaving them fairly flat on the time (not sharp). It sounds like this might be wrong? I usually want my chain to be a bit more aggressive, so I generally just take several strokes off of the rakers every time I sharpen. I have found (the few times I have done it) that leaving them at the indicated place that the guide would leave them makes it not grabby enough. I also took a lesson from a mate who was in the forestry service fighting forest fires. He said that the professional loggers he would run into would take their rakers down an extra 10 strokes or so just to make them cut that much better. I have to say that this guy really knows how to sharpen a chain and he has been giving me a few lessons. But I don't think he's particularly scientific about it - just does it by feel. Anyway, do my rakers need to be "sharper" on top? As in pointy perpendicular to the direction of cut? Like a rooftop?

1) Notice how my gullets are fully cleaned out, this helps to clear sawdust and can be significant on a wide cut

I'm afraid I don't know what you mean by gullets. Could you please clarify?

2) Notice the steeper angle of my raker top, and also how Will's is not steep.
My rakers are wide so I put a steeper angle on them. If the rakers are narrow it's not as important.
Raker top angles (not the same as Raker Angle - see above) contribute to the extent of cutter bite.
It might not appear so but rakers actually slightly penetrate the wood allowing the cutter edge to tilt more and thus to penetrate more wood and take a bigger chip out.
It's the subtle combo of raker angle, hook, and raker top angle that makes a saw self feed although there won't be much self feeding in 50" wide cuts.

I was wondering about this. I had been tending to just take the top off of my rakers like a flat-top hair cut and was worried about what this would eventually do to their profile. It sounds like I should be paying more attention to what that profile looks like and that filing rakers is more complicated than I thought. I am also again thinking that I need to file them differently than the way that I am, which is making them flat on top both directions so that they would have less tendency to cut the wood.

3) You have a lot of resin on the chain. I would run more aux oil. Pine resin is a mongrel (that's why I rarely cut pine) but consider having a pump pack of diesel on hand and squirt that on the chain. 3/4 bar oil and 1/4 diesel is another alternative.

After all that you probably think, he has really studied this in detail and that I'm some kind of anal retentive nerd but that's just my science training coming out.

I am running vegetable oil on the auxiliary end and I generally just set it to drip on the uphill side of the bar tip where the chain meets the bar. This results (I think) in some oil getting pulled into the chain before it goes around the nose and some oil running downhill across the bar and into the chain groove on the downhill side (after the chain has made it around the nose of the bar). It is no problem to increase the flow rate. When would I squirt the diesel on the chain? In between cuts to clean it or what? Is using veg oil part of my problem? I run Stihl bar oil on the chainsaw end.

For what it's worth, this is also not exactly green oak. The tree stood dead for a number of years (maybe as many as 5?) and then has been cut and lying for another 2-3.

I don't think you're a nerd at all, and as a sciencey-type guy myself I appreciate the thought that has gone into this. I have read post 106 in the 101 thread a number of times and couldn't get my head around it. I knew that I would eventually get to the point at which I started paying attention to sharpening the chain myself and it would then start to slowly make sense. With your help, it's slowly starting to make more sense. Thanks for being patient with me.

I'll probably wait to see how you respond to what I said above and then try to sharpen a tooth again using what you've taught and post a picture for criticism if that's OK.

Thanks!

 

[BobL]

I see immediately what you mean regarding hook or top plate cutting angle (I think) and (I think) I understand why this matters (it's the same reason having longer fingernails work better for opening pull-tabs and for scratching). I have been using a .404 file to do my filing and see why you would say I could use a smaller file to get more hook. However, could I also achieve more hook simply by changing the angle at which I file a bit? Turning the file out of parallel with the TPFA and a bit deeper into the side cutter should result on more of a "belly" such as you and Will have in your profiles. Would that work? The problem I foresee with that is that it might tend to reduce the cutting effectiveness of the side cutting portions themselves. Thoughts? I don't mind just getting a smaller file, but what size do you recommend that I get in that case?

If you turn the file out of parallel you will change the "top plate FILING angle" which is different to the "top plate cutting angle". The two angles should be formed at the same time
To produce more hook'
a) bite further into the belly of the cutter with a slightly (and I do mean slightly) larger file. See RHS of image below - there'd ring has more hook than the blue. (sorry I got those around the wrong way in the post above)
b) It sounds counter intuitive but, move the same file you have been using a whisker downwards by using the same file in a slightly (once again I means slightly) smaller file guide. This moves the file down which means the file produces a more pointed cutter.
You can of course mix and match a) and b)
If you want cutters that don't need much sharpening use a smaller file and in a large file guide.
If you want extreme hook use bigger file in a smaller file guide.
I'm using a combo of the two, so they slightly cancel each other by using a a 13/64" (as opposed to 7/32") file in a 3/16" file guide otherwise the chain bluntens too quickly.
Instead I prefer to increase the size of the cutter bite by finessing the raker top - see below.

As for my rakers: It sounds like my cutting angle is close, if I am reading that right, to "normal" but not nearly big enough for what I am doing. So I am getting I need to set my rakers quite a bit lower. Correct? I guess I need to find a digital angle finder and get one to help. Do you recommend a particular one?

I have several different DAFs, my favourite is the Beale Tilt box but if you are on a budget then one of these will do the job
http://www.ebay.com/bhp/digital-pitch-gauge
The plastic attachment can be removed to make it easier to use.

When I'm running the mill I sharpen with the chain on the mill.
Cutters are touched up (2-3 strokes just to remove any glint) after every tankful of mix or after every cut whichever comes later.
Rakers are set with a digital angle finder in the shop but in the field I just give the rakers a couple of swipes after every 3-4 cutter touch ups.
By the end of the day the raker angles are still around 6.5º, if I get slack about swiping the rakers the cutting rate will drop significantly below about 5.5º and be quite slow and make a lot more powder at less than 5º

However, I am a bit worried about the cutting part that the raker itself should be doing based on what you said. I usually file straight across the tops of my rakers, leaving them fairly flat on the time (not sharp). It sounds like this might be wrong?

Flat rakers means you need even more hook to get the cutters to bite properly. This means a more pointy cutter which will go blunt quickly.

I usually want my chain to be a bit more aggressive, so I generally just take several strokes off of the rakers every time I sharpen. I have found (the few times I have done it) that leaving them at the indicated place that the guide would leave them makes it not grabby enough.

When a 3/8 or 404 chain is new, a standard 0.025" raker gauges will form 5.7º raker angles (that's why new chains cut OK but even they need "fixing"), as the cutters wear and are filed, the standard raker gauge produces a smaller and small raker angle so the rakers have be filed even more that the amount specified by a raker gauge. By the time the cutters are worn out the rakers should almost be gone.

I also took a lesson from a mate who was in the forestry service fighting forest fires. He said that the professional loggers he would run into would take their rakers down an extra 10 strokes or so just to make them cut that much better. I have to say that this guy really knows how to sharpen a chain and he has been giving me a few lessons. But I don't think he's particularly scientific about it - just does it by feel. Anyway, do my rakers need to be "sharper" on top? As in pointy perpendicular to the direction of cut? Like a rooftop?

Although I know one miller that does put a point on his rakers, when I tried it I found the vibe was greatly increased so I still leave mine sloped with a slightly rounded top.
You have to determine what works for you wood.

I'm afraid I don't know what you mean by gullets. Could you please clarify?

Gullet is the gap between the cutter and the raker. These should be cleaned out e.g. the little metal pimple as shown outlines by the red box should be removed.

I was wondering about this. I had been tending to just take the top off of my rakers like a flat-top hair cut and was worried about what this would eventually do to their profile. It sounds like I should be paying more attention to what that profile looks like and that filing rakers is more complicated than I thought. I am also again thinking that I need to file them differently than the way that I am, which is making them flat on top both directions so that they would have less tendency to cut the wood.

Don't fuss too much about the raker shape, the raker depth is much more critical and just don't leave the raker dead flat and add a bit more slope than you are using.

I am running vegetable oil on the auxiliary end and I generally just set it to drip on the uphill side of the bar tip where the chain meets the bar. This results (I think) in some oil getting pulled into the chain before it goes around the nose and some oil running downhill across the bar and into the chain groove on the downhill side (after the chain has made it around the nose of the bar). It is no problem to increase the flow rate. When would I squirt the diesel on the chain? In between cuts to clean it or what? Is using veg oil part of my problem? I run Stihl bar oil on the chainsaw end.

By vegetable oil I assume you mean canola? You can squirt the diesel on the chain while the saw is running - this is where t helps to have a remote and lockable throttle which frees up a a hand to do other things.

For what it's worth, this is also not exactly green oak. The tree stood dead for a number of years (maybe as many as 5?) and then has been cut and lying for another 2-3.

Sure I can appreciate that

I don't think you're a nerd at all, and as a sciencey-type guy myself I appreciate the thought that has gone into this. I have read post 106 in the 101 thread a number of times and couldn't get my head around it. I knew that I would eventually get to the point at which I started paying attention to sharpening the chain myself and it would then start to slowly make sense. With your help, it's slowly starting to make more sense. Thanks for being patient with me.

The greatest driver to get me to understand all this was tackling harder and hard wood. As the going got tougher I had either work it out or give up.

 

[pa.hunter]

that's a biggen!

 

[Yellowbeard]

All right BobL, I have taken all of your advice to heart and tried my hand at sharpening. Without beating it to death, I am just going to post pictures of my teeth after I sharpened them, cleaned out the gullet, and changed the angle on the rakers and lowered them. I don't yet have a DAF, so I was eyeballing the rakers (which, I know, probably isn't the best way to go) but I thought I would throw this out and see what you think. I used some trig to see if I could come up with angles post filing and think that I need to take more off as you can see below.

Reading your above comments it seems that in one place you are saying that the rakers should not be flat and in another that they should not be pointy, but I think it's because I meant the rooftop shape to be going the opposite direction to the direction you took me to mean. I'm asking, basically, should I sharpen them kind of like a shark fin (tapering from fat to thin from bottom to top when looking down on them, so, perpendicular to the bar in the same direction that bolts would go through the bar to attach the bar to a mill frame)? I think from your answers above that this answer is "yes."

By the way, for what it's worth, as an educator, I was very impressed with the diagram you posted with different coloured circles on it above; very immediately got what you meant by that.

Thanks for all your patience with me! I hope I am not being a horrible student.

 

[Yellowbeard]

I think I may have figured out another way to ask what I am trying to ask about the rakers. If the raker is a bloke's face, facing left in all my images above, with a rounded forehead sloping back (the part I just lowered the steepness on), his hair should be more like a mohawk and less like a flat top when viewed looking down the bar from the nose to the powerhead. Correct? Mine are currently like a flat top, so I think I need to mohawk them which can be accomplished when I lower them a bit anyway.

 

[BobL]

The cutters look much better but the rakers do need dropping to at least 6.5º

Reading your above comments it seems that in one place you are saying that the rakers should not be flat and in another that they should not be pointy, but I think it's because I meant the rooftop shape to be going the opposite direction to the direction you took me to mean. I'm asking, basically, should I sharpen them kind of like a shark fin (tapering from fat to thin from bottom to top when looking down on them, so, perpendicular to the bar in the same direction that bolts would go through the bar to attach the bar to a mill frame)? I think from your answers above that this answer is "yes."

Shark fin is a good description - not quite sure about the rest but maybe it doesn't matter.

Check these out - this is super nerdy stuff so apologies for those that wanna "just flog a saw and make some noise" .

Just a reminder to others that "raker top angle" is not the same as the "raker angle" -

The "raker angle" is that angle shown in YBs photo below as 5.1º.
The raker angle is formed between lines made by
a) the line starting out at the tip of the cutter and parallel to the bar
and
b) the top of the cutter and the point at which a straight line from there touches the top most part of the raker - this may not be the back of the raker but closer to the front of the raker especially if the raker is flat, by which I mean parallel to the bar.

Note: In YBs photo because the top black line is not parallel to the top of the pink box so the raker angle is less that that indicated.
Before I measure/calculate the angle in photoshop using pixel counts I rotate the image so that the bar is exactly horizontal.

OK see the line on the raker marked with the red arrow above, that should the minimum slope of the raker top, and the min angle that raker grinders and files should generate for a basic raker shape.

But many aficionados finesse that even more.
This is Mtngun's raker shape - totally flat but seriously sloped. I'm pretty sure he use a grinder.

It's not visible in this photo but he ended up using a lot of hook and a high raker angle (remember this is not the angle on the top of the raker - see above).
The combination of all this was his cutting speed was consistently one of the fastest reported on AS for softwoods back when he was posting.
This will be super grabby so be prepared for more vibe and wear and tear.


Finally this one

The orange line (raker top flat and parallel to the bar) will have the least penetration into the timber - more dust
The green one follows the slope of the guide line marked on some rakers - this should be better but may not be severe enough especially in softwoods.
The brown line is Mntguns and also what another member "Sawchain" used - serious penetration and as said above, be prepared for serious vibe.
I prefer using the blue or red lines and putting more raker angle on as this combo maintains a reasonable cutting speed and does not generate too much vibe.

By the way, for what it's worth, as an educator, I was very impressed with the diagram you posted with different coloured circles on it above; very immediately got what you meant by that.
Thanks for all your patience with me! I hope I am not being a horrible student.

Cheers YB
BTW I have seen very few "horrible" students in my time. Most learning and teaching problems comes from a failure of the teacher and the student to understand where each of them are coming from and where they want to go.

 

[Yellowbeard]

I was trying to keep that line parallel to the bar and thought I had done so but you have shown that this was wrong - sloppy work on my part - sorry.

I've done more work on rakers since then, trying to get that shark fin shape. I'm also trying to get the rakers more like the blue line you show as your preference above (I was actually just trying to match the rakers you posted actual pictures of above). I am using a grinding wheel, btw. As I work more and more I feel like I am getting a better idea of how to sharpen each part. Of course, I worry that I'll accidentally ruin a chain but I guess it's worth it for the learning and experimentation.

I feel like I should go take a couple of pictures of what I have got them to as of now so I'm going to go do that.

 

[Yellowbeard]

OK, here goes:

I tried to make sure the image's bottom edge was parallel to the bar this time to make things easier. I used your pink box method to check.



This one was close.





Seem to have gone a bit too far on this one.





Close again here.

Is it going to screw things up that they aren't too exact?

Tried to get close ups of how I am attempting to shape the rakers below.





I was trying to make their tops a bit knife edged so that they would score the wood in the way I think you're describing. How am I doing?

 

[Yellowbeard]

Thanks again for spending all this time helping. I greatly appreciate it. Cheers to you as well.

 

[KiwiBro]

Here's a cheap digital angle finder, to help with the raker angles, sold by someone I have bought from and have had no trouble with, after Bob alerted us a while back to these cheapies.

http://www.ebay.com/itm/New-LCD-Dig...510025?hash=item5b1de41209:g:KgsAAOSwwbdWKHcF

 

[BobL]

I tried to make sure the image's bottom edge was parallel to the bar this time to make things easier. I used your pink box method to check.

Yep - good method. Gullets look better too.

This one was close.

Yep that one is OK

Seem to have gone a bit too far on this one.

Yep too far - normally I would take some swipes off the cutter to lower the raker angle back to closer to where it should be but in your case try it and see what happens.

It looks like you have filed the back of the rakers to make them more shark like? Be careful as this might trap saw dust. If anything just lightly file the raker back edges round with a needle file so that the sawdust slips past easily.

Is it going to screw things up that they aren't too exact?

It won't screw things but you wont get smooth cutting because it will increase the vibe.
What happens is the cutters with higher raker angles will wear (go blunt) quicker so when you go to sharpen (touch up) between cuts do it only to remove glint.
The more worn or glintiest cutters will thus get more filing and this will lower the raker angle back to some sort of average.
I shoot for +/- half a degree but if one or two come out a bit high up to 1º too high they will be fixed in future touch ups so I just leave those.

This method of sharpening does not require the cutters to be of the same length or the rakers to be all of the same height as long as the raker angles are more or less the same.
However if you end up with too many cutters that are all too long or too short on one side, e.g. all the LHS cutters are longer than all the RHS cutters this might cause a problem
Eyeballing this is good enough so if a cutter looks too long I add a couple of extra swipe when touching up.

I was trying to make their tops a bit knife edged so that they would score the wood in the way I think you're describing. How am I doing?

I wouldn't change too much in one go especially as you cannot go back too easily once you do that.
Just make the rakers more rounded over than flat to start with and finesse it from there

 

[Yellowbeard]

OK. I am just shocked. Had someone told me "I can double your fuel economy and speed with this one simple trick," I would have said "suuuuure you can." However, one lesson with the BobL school of chain sharpening and I did better than that. Cut through the thickest areas of this log that I have cut so far today and what had been taking me four tanks took me slightly less than TWO.

I just can't believe how much better that was. Things had become a bit of a grind but today was just pure pleasure.

BobL, I can't thank you enough. What is more, I finally am starting to feel like I am beginning to understand the mysteries of the chain and how it works (not totally understand, mind you, but start to). I wish I were going back down under soon so I could buy you beers until you passed out.

It was a wonderful, wonderful day milling.

 

[BobL]

OK. I am just shocked. Had someone told me "I can double your fuel economy and speed with this one simple trick," I would have said "suuuuure you can." However, one lesson with the BobL school of chain sharpening and I did better than that. Cut through the thickest areas of this log that I have cut so far today and what had been taking me four tanks took me slightly less than TWO.

I just can't believe how much better that was. Things had become a bit of a grind but today was just pure pleasure.

Good to hear from another satisfied customer

BobL, I can't thank you enough. What is more, I finally am starting to feel like I am beginning to understand the mysteries of the chain and how it works (not totally understand, mind you, but start to). I wish I were going back down under soon so I could buy you beers until you passed out.

From the other side of the world I think I can hear a student's "Ah - Ha" moment has kicked in - that's where I get my jollies
In terms of beers, you have one for me and I'll have one for you.

Now I hope you realise that this is just the beginning.
I encourage you to continue to explore this a bit more as there are more small gains to be made.

Try this,
1) cut a slab and
2) then take two swipes off the rakers
Repeat 1&2 until the chain starts to grab and bog down in the cut, now measure the raker angle and you will know how far the rakers can be taken down.
To go backwards take 4-5 swipes off the cutters.

Eventually you will find a real sweet cutting spot that you will drift in and out of and staying on the spot becomes the aim of the game. Gosh that sounds like something else!!

The benefits are not just less fuel, there's less load/ wear and tear on the power head, and less wear and tear on you.

 

[Yellowbeard]

I can only wish that my students have experiences like this from my classes. I have definitely seen light bulbs go in before but this... Man.

Maybe I will get closer now that I am teaching hands on things where they can actually get immediate obvious benefits from something I show them. That's a bit less obvious when I am befuddling them with philosophy.

 

[BobL]

Maybe I will get closer now that I am teaching hands on things where they can actually get immediate obvious benefits from something I show them. That's a bit less obvious when I am befuddling them with philosophy.

I was the same, preferred teaching in Physics labs than Physics theory, which very few students could grasp, and most ended up trying to memorize rather than trying to understand it.

 

[Yellowbeard]

So I guess you were a physics teacher then? What level?

Also, why not this?

http://www.madsens1.com/bnc_teeth_types.htm