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plunge cuts - do's and dont's

Started by BC_coops, January 10, 2005, 10:00:45 AM

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BC_coops

Would greatly appreciate a little help and guidance on tackling this one ...

I've got a 40" cucumber magnolia near my house which is dying ... plus its got leaves like an elephant's foot, which are a mess when they get wet ...

the 350x350 upload requirement means I can't put all the info on one pic, so (A) the horizontal section looks like this ... (I hope I'm doing this right)



Note that because of fencing, there is no escape route on the left side (standing at the tree and facing the target area).  Thus, the last cut will have to be a pushcut into a holding strap, made from the right side and on the exit path

(B) the vertical section looks like this ...



I'll need to cut the notch from both sides, so I'll use as small a saw as possible (20") and probably do it in "baby steps."

(C) because of the irregularity of the tree, the plan for cutting out the felling cut with a 20" bar (say a 346) might look like this



(D) a 24" bar (say a 372) cleans up the cut plan, but requires a plunge -- and this is where I thought I'd ask for comments



On a plunge cut, basically the principles are (1) keep the hammer down -- use the right hand for one purpose only, gripping the handle  and controlling the saw (2) hold on tight, no matter what how much the saw might try to shuck and jive in the cut (don't use an undersized saw) (3) never, never let the saw "get on top" or take control away from you, which is what that red-tipped end of the bar will want to do (4) ???

(E) Make the plunge cut first, so the the tip can be kept in clean wood, with no chance of biting into an open kerf from an opposing cut, which would try to draw the blade into the "easy cutting area" of the open kerf and jam the bar, resulting in kickback.

Then make the swing cut.  In order to keep the kerfs from crossing, angle the plunge cut upward a little, about an inch at the tip end fully plunged.  Angle the swing cut downward about an inch, so that it doesn't "find" the plunge kerf and jam up the bar.



So, there's my plan of attack ... I would appreciate comments, esp regarding safety.


Ianab

Hi BC

Looks like you have thought it out pretty well.
I'd go with the bigger bar and plunge cut myself. Once you get used to doing it you may find it's actually your preferred method of felling. The trickiest part of the plungecut is the initial entry into the tree. Make sure you enter with the lower corner of the tip first. Once the bar is part buried in the tree straighten the saw up and push all the way in. If you try and push the tip straight in it will kick back for sure. Once the bar is burried in the slot it may jiggle around a bit but cant really kick back in the normal (dangerous) sense of the word. As you have said, use a sharp chain and keep the speed up.
I haven't had any problem when the cuts from each side overlap, but unless you have a real good eye / hand they probably wont meet exactly.  ;)
As usual.. take care, but looks like you have planned correctly.

Cheers

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

beenthere

BC
Great drawings!  Looks like you have a good plan, IMO.

My only comment, based on experience with a leaning white  oak tree last spring, would be to initially leave more backstrap than what you have shown. Then after each plunge cut (I would plunge from both sides) is 'finished' to the hinge on each side , place a wedge on that side before going to the other side (I would saw in from both sides twice, adding two more steps to your plan),  and then saw the backstrap out last (as you have shown, but IMO leaving plenty to avoid an early breakaway before you finish the cuts in from both sides).
That 'early breakaway' was a surprise on my white oak, but it was a big tree and split off a chunk of wood that went down into the roots of the tree. No loss, but it just didn't look 'pretty' and could have been avoided if more backstrap was left.
I like your approach and use it often when cutting leaning white oak on my east facing hillside. They just don't want to grow straight up on the slope.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Kevin

Use the bottom of the bar to plunge .
It looks like you'll have ample room for wedges but because of the back strap you won't be able to get much lift with them unless the tree is a head leaner.
An option would be to change the holding wood which you can nip away at and set the wedges at the same time.



Make the notch and inspect the condition of the wood .
Bore in using the bottom of the bar well behind the hinge and cut up to the hinge afterwards.

Ianab

It does depend how much lean the tree has.
If it's leaning heavily then wedges wont really be needed, and the back strap will be under tension, actually holding that side of the tree down.

Thats what Beenthere is talking about, get the hingewood right first, then cut back to the holding strap last. Leave a bit bigger holding strap if you aren't sure. Complete the plunge cut to the holding strap from your escape side, incase the strap tears out prematurely.

If the lean is only slight and you need to use wedges to tip the tree over that can still be done. Drive the wedges in on each side of the back strap then cut the back strap just below the wedges ( like you intended anyway). If the tree falls, good, if it doesn't drive the wedges till it does.

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Kevin

Here's another method that will leave you with ample hinge wood without a plunge and you can still use wedges...



I should add that you shouldn't limit yourself to just two wedges on a large tree.

Larry

That drawing is just pretty dang cool.  

Few comments on the cutting with the 372.  In your top drawing you have an arrow that shows "pull" so I am guessing that is the heavy side of the tree which is on the right looking down....so I would make my first cut on the right side of the tree.  Just my way but I would make plunge cuts on both sides of the tree because for me it is easier to get a level and even cut behind the hinge and then saw to the back strap.  When making that first cut I would also pull out my magic marker and put a mark on the bar so I know how deep I am cutting into the tree.  Since the first cut is always on the heavy or most dangerous side of the tree you don't want to cut any more fiber than necessary.

Rule of thumb is your tree is going to fall half way between the pull arrow and lean arrow.

I won't comment on your conventional notch and hinge as I went to the open face notch long ago and believe it to be much safer...jmo as OSHA still thinks the conventional notch is ok.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

Kevin

That's the problem with telling someone how to cut a tree without seeing it.
It could be straight as an arrow but with all the branches on one side it isn't going where you want it unless you make the proper cuts.
Anything that gets posted here is just a general rule of thumb.

Kevin

Another thing to consider is squaring the trunk if you need to prior to making your cuts.


Larry

Thought a couple of pictures might help out.  Get the tip of the bar in and the rest is easy.  The plunge goes really really fast with any pressure at all on the saw so the main thing to do is concentrate on keeping the bar level and  in proper relationship to the hinge.





The bar is in about as far as I want....see the little squiggly mark on the bar...now I'm gonna sneak up on my hinge to get the exact thickness I want.


                  


Cut to my back strap or holding wood and go to the other side of the tree.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

1953greg

 bc,  if your technique is half as good as your schematic you wil have no problem.  thumbs  up!            8)       1953greg
good day    greg

leweee

BC just a few pics;
Starting a plunge cut (bore cut)

A forward leaner

Cutting the back strap

Forward leaners have the potential to barberchair if the hinge is too thick . To lessen this potential I plunge cut the hinge on the same plane as the back cut (removing the center of the hinge)

sorry for the poor picture quality
If this is a valuable timber tree, this method prevents center pull of fibre in the butt log(any fibre pull is limited to the two smaller hinges towards the outside of the butt log.
As stated earlier ever tree is different, so there are many considerations to be taken into account. ::)
Play safe & have fun  ;D
 Lewis
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

OneWithWood

A lot of good advice here.  One thing I have learned when making a plunge cut in a large tree is to pull up on the motor slightly as you make the plunge.  This will offset the natural tendancy of the cut to angle upwards due to the weight of the sawhead.  If you have trouble getting the two plunges to meet the small down angle you introduce by lifting the saw head will compensate and guarantee the two cuts meet.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

BC_coops

thanks guys ... there's a whole lot of good stuff there, so I'll thank you all as a team.

especially the reminder on keeping the pullin' side of the bar "to the wood," and the pushin' side of the bar running free in the trailing kerf, and about keeping the chain sharp (and the fuel tank full)..

I have been trying out the Oregon Vanguard chain ... so far, when new, it seems to cut purrty & smooth, even in a plunge ... drives in smooth in soft wood and there's no gagging on the haul, so I think I'll stick with it.  I can see the rakers will be a little different to file, but that might just a learning curve thing, since they look like they might be easier to file than rakers on LP-LJ.  My 2¢ is that the anti-kickback design of that chain is very thoughtful, and would be useful on a plunge cut ... so I'm going with it.

I'm going to take up beenthere's idea of beefing up the backstrap, and maybe nicking off the corners, which the drawings don't show.  Also, plunging the "gut," or center of the hingewood at the same level as backcut.

initially I had planned a fully opened face at the hinge, but then I decided I didn't want the butt end to hang on the stump, which at 36" is a little high ... if the tree sticks on the stump, the top of it will be 7 ft in the air.  My preference is that the hinge snap good and the pole drop to the ground (and upper limbs crush on the bounce, hopefully lessing spring and roll-over problems when down).  The major limbs are trees in themselves, so they will be dropped and cleared before hand.  (Gotta remember to free the winch in this case.  I haven't had it happen yet, but I imagine that tree bounce could probably throw a car around pretty good. lol-?)

So here's the final plan ...

start with cutting center of the hinge at backcut level



make the backcut by plunging both sides, and leaving a 6" strap.  Make the first plunge on the weaker/heavier/more dangerous side.  I've shown the wedges at the end of each cut.



when I get down to cutting the backstrap with a standard eastern handle, I end up having to use a pushcut, since the right side is fenced off and is closed off as an escape route.  So, I will have to finish from the left side of the tree (looking back at the tree from the target area).  ... my preference is, if possible, to *not be on the push side of a bar if something happens and I gotta scram.



but, if I add a western style full wrap handle, notice how much cleaner the dropcut becomes  ...



So, I'm going to invest in a fullwrap handle (even if chainsaw manufacturers apparently don't want us to use them on the east coast - lol.)  I guess there must be at least one good reason for the full wrap handle ...

Any special dangers on using the "western side" of a full wrap handle ???

Again, thanks.  Some really helpful posting here, and I really appreciate it.

Jeff

So, when is the planned date of attack on your plan of attack? :)
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

BC_coops

man ... some times, it feels like I been gettin' ready, to get ready, just to get ready.  And all my life at that too.  My mama even told me, Son, you was born late.  (I was also born on a train wreck on Long Island Railroad, in 1947 -- not that I don't like trainwrecks. javascript:cheesy()
Cheesy )  It seems like I still ain't caught up yet.  And, it don't matter how fast I try and run  ... (somebody's gotta do the work and feed the greed, for all them LBO bankers, you knowjavascript:lipsrsealed()
lips sealed ).

I don't climb, and I work slow on things that I think are dangerous.  My limber is a great old school tree man.  He's easily in his 80's!  Name is Otis Sisk, from Culpepper VA.  He comes round every month or two.  He's scared of this tree too, so it'll be a while before I get the limbs dropped.  I want the trunk for myself.  It's an inbetween project.

Stephen_Wiley

Quote......................I don't climb, and I work slow on things that I think are dangerous.  My limber is a great old school tree man.  He's easily in his 80's!  Name is Otis Sisk, from Culpepper VA.  He comes round every month or two.  He's scared of this tree too, so it'll be a while before I get the limbs dropped. I want the trunk for myself.  It's an inbetween project.

Might I suggest that if your ' willing' to tackle the trunk.  That you quit scarring 'Otis' and hire an Arborist to climb and delimb the tree for you. Possibly one who is younger than 80, LOL.

If $'s are a problem,  might get creative and see if a local Arborist will work a reduction of $'s to use your tree as a teaching tool.  Make certain the public is informed of his good deed and invited to watch.  The exposure will most likely bring his business new clients.

Added benefit you may also 'find out' additional flaws or benefits to your felling method.




" If I were two faced, do you think I would be wearing this one?"   Abe Lincoln

rebocardo

I finished up a white oak tree that had branches at and near 19 W"x38 H"x80 L' , let me tell you when they hit the ground from 40+ feet they make quite the impact. Even the smaller 12-14" ones from 80 feet up pretty much leveled everything. I thought I was going to have to worry about springboards.

Hardly, the 19w ones crushed and broke everything they fell on under four inches.

>  I imagine that tree bounce could probably throw a car
>  around pretty good

If the tree can possibly fall into anything, I would still put deadmen lines on it. If you anchor the lines so they have some droop with a tow strap (the ones that stretch and rebound) it will take a good amount of bouncing without pulling the tree down or breaking. Same if anchored to a truck.

I use 2" x 6 foot ones with the double loops rated for 8k.  Though on a tree that size I would step up to the 30k ones.

The come-a-long will probably be the weakest link unless you make custom length cables on site.

rebocardo

BC,

I did not see it mentioned, but, you are turning this into lumber I hope? I saw someone post that the magnolia woods are worth something like $10+ a foot kiln dried.


BC_coops

whoa! $10 a ft -- that's got my attention

how do I go about finding a miller with a kiln?  I've got room here to store it for air drying, if that's an option.  and then to whom do I sell it?  Now that we've let ADM bankrupt our farmers, since they can sell only to ADM-Cargill etc., I was imagining that it was pretty much the same for millers ...

My first plan for dropping the tree was pretty much as you handled your oak.  I was figuring on a high speed drop, where the drop is started with a dynamic pull with a 20 ft 10 T nylon tractor strop, and a 6T hydraulic winch.  (Once the tree is accelerating toward the ground, release the winch so that if it bounces, it just unspools the line.)  The first branch to hit would be a weak 24" branch, whcih divides right away into two unhealthy 14" branches.  It comes out to the left, at about 45° to the fall line, and as it is diseased, would probably snap.  At the break point, the branch would form a fulcrum which would kick the trunk momentum over onto another branch, also 24", which comes out at 90° from the trunk and at 10' turns 45° upward for about 35', and which is also 45° from the fall line, on the right side.  When the falling trunk lurches over to that side, from the kick of the first branch, I recon it will also snap from the momentum.

Aside from 6" top trash (which is not to be ignored), that *should pretty much put the trunk on the ground.  Now the downsides -- if only one of the two branches breaks, the trunk still ends up on the ground, making a "Y" with the surviving branch.  If both branches survive, which would require a very gentle drop, the trunk ends up with the top pointing up in the air, at about a 20° angle.  At that point, if my winch and a 2X pulley was unable to roll it over and get it on the ground, than I would have to bring in another winch, and that failing, a crane.  I would also probably make a little "snap assist" e.g. a 5-6" cut into the bottoms of each branch, say about 1-2 ft out from the trunk.  When the branch top hits the ground, and the tension is transferred to the bottom of the branch at the trunk, I would have shifted the point of maximum strain inward, and removed the most of the cross-section which the branch would have needed to survive.  snap.

I still might go to that plan, as I got one price for delimbing of $750, which is out of reach for me right now.

slowzuki

I only noticed the words anti-kickback chain in there, if this is the same stuff that as it goes around the tip a little ramps guards the cutter, it is near useless for plunge cutting and can be dangerous as you end up forcing the saw and working in the cut too long.

SwampDonkey

All very good information and I especially like those schematics. That takes some time to put together, thanks BC_coops for that. Also, thanks to everyone else on technique and diagrams. A great big


Play safe  :)
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

BC_coops

thanks everybody -- I had a lot of fun doing the diagrams (I used to be an autocad draftsman, so it was pretty straightforward for me.  I used a little $50 -1998 dollars - autocad program called autosketch.  Once I created an object called a "20-in chainsaw," it was only a matter of putting one where I needed it, rotating it to position, and assigning a layer or color.)  I really appreciate all the helpful feedback.

thanks slowzuki--I did notice on my trial runs with the "Vanguard"  and LP chains, after plunging in and then sweeping down say 10", if I relaxed the pressure even just a bit with the Vanguard chain, like to shift my feet 6" or so along the cut, so that my stance could "follow the cut," and during the weight shift thereby "accidentally" took the pressure off the tip and let it "catch" some of the kerf, the Vanguard some kind of kicked and bucked, and tried to take the saw out of my hands and work the tip back out of the cut.  More so than the LP chain, which seemed easier to "keep the tip in cut."

But, I had also just sharpened my LP chain (bumper drive links) and had moved the rakers a little lower than 025 spec.  Whether plunging or straight bucking, I am noticing that *that particular LP chain seems to naturally "pull" itself into the cut easier than the Vanguard.  (I was using an underpowered 540 on 20" bar buried about 18" in a Holly for the comparisions)

For some reason I didn't want to "set" on the bumper spikes "into" a plunge cut.  Probably because I wanted to know exactly what my tip was doing in the cut, and where it was.  And if the tip did react and try to kick out, I didn't want to be "gliding (e.g. relaxing)" on a bumper spike ride, while at the same time creating a high speed fulcrum near the center of gravity of the saw.  Plus the chain unloads the cut better.  Anyway, now that you mention it, it did seem like I am a little more tired at the end of Vanguard cuts, so I'm going to move back to the regular LP LG chains.

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