"Chattering" during bore cuts

[John Mc]

I'm having a problem with my chainsaw "chattering" or grabbing and bouncing around when I try to bore cut with it. It goes OK when I start, using the lower half of the tip. After I've made a bit of a pocket, I swing it around to bore straight in and it grabs and jumps a lot. It's acting like a bunch of mini-kickbacks.

I just sharpened the chain. Tooth shape looks normal. I filed the depth gauges using the "hardwood" side of my depth gauge tool. I'm thinking that I must have got the depth gauges too low, despite using the tool. Any other thoughts, or am I on the right track here?

Saw is a Husky 357xp with 16" oregon bar and 3/8" pitch full chisel Husky "48" chain (same as Oregon 73 series?). I do all my own sharpening - with a hand file and guide. Had this problem when I was first learning to sharpen, but not recently. I'm thinking I must have goofed something up (or maybe my depth gauge tool is off?)

[beenthere]

Sounds like depth gauge possibly too low to me too.

Be sure you are running at full throttle. Friend of mine has the habit of trying to go slowly into the bore cut by running at part throttle. He gets a lot of chatter, and enough that he doesn't want to bore cut. I can't get him to understand that its full throttle in the wood, and only less than that when it isn't in wood. He does a lot of clutch work.

Sometimes, when boring I just put a bit more pressure, pushing on the saw into the bore cut. That is if I start getting any bounce or chatter.

[Captain]

Are you using a full comp, skip or semi skip chain?  Sometimes chatter is from space between the cutters.

Captain

[nmurph]

if the chain is not grabbing while you are not boring, then likely you are not running the saw fast enough. as mentioned above, once you have done the initial cut with the tip of you saw you should be at or near full throttle as you rotate you tip into the cut. also make sure you are keeping good pressure on the bottom of the tip as you do so.

[John Mc]

Chain is full comp (no reason for skip or semi-skip on a 16" bar with a 357). Cutters still have a lot of life left on them, so it's not like the performance changes you sometimes see at the en of a chain's life.

I'm at full throttle - I don't cut at less, especially when bore cutting (I'll admit to occasionally letting off when trimming small limbs around 1" or less - a habit I can't seem to break).

I tried a couple of times with light or firm pressure. In this case, more pressure just seemed to make it worse - another indication of depth gauges too low?

[beenthere]

Sounds like you have it figured out. Other bases well covered, as I see it.

[John Mc]

Well, that's what I suspected... but I was hoping something else might turn up. Not much to do but use it for bucking until I've worn down the teeth a bit and resharpened a couple of times.

[Kevin]

You can't bore straight in.
Always bore with the bottom of the nose until you cut through to the other side then use the belly of the bar to even up the hinge and back strap.

[John Mc]

Kevin -

I hadn't heard that one before (you can't bore straight in). I know you have to get it started with the bottom of the nose, but I've not had trouble going straight in once I have the pocket started. I bored myself a chainsaw scabbard down the length of a 2X6 at one point (I needed a chainsaw holder that I could clamp to my tractor). I couldn't do that if I were always using the bottom of the nose... I'd have come out the side of the 2x6. I've always just needed the pocket to get started, and "contain" the bar and it's worked great.

[Bro. Noble]

It sure sounds like the drags to me.  We just finished cutting a little over 3000 utility poles and everyone of them was borecut.  We didn't have any signs of chatter until the last two or three days we cut.  My son did most of the cutting (and skidding  ) and takes pride in having his chain perfectly sharp and the drags filed by a gage.  The only thing that I can see that changed is that we bought a new file to file drags

[Kevin]

John,
If you want to eliminate the chatter which is the chain attempting to kick back, bore with the bottom of the bar nose.
What is the raker height?
.025" to .030" is what you should have.
No problem using the hard or softwood gauge if you know how much you are filing off.
High speed, a sharp chain and boring with the bottom of the bar nose will get rid of your problem of chatter.

I bored myself a chainsaw scabbard down the length of a 2X6

Different grain will give you different results.

It goes OK when I start, using the lower half of the tip.

I think you may have already answered your own question with your first statement.

[John Mc]

Kevin -

Thanks for the tips. I don't know what my raker height is... it's just whatever the hardwood side of the depth gauge tool makes it come out. It's always worked in the past, on a variety of trees and grains. I do have two of these tools, supposedly identical. I'll have to check with both and see if there is a difference. Here's a link to the depth gauge I'm using. It's sold by Husqvarna. I'm using the one on the left. Up to now, I've found it works much better than the ones sold by Oregon which span two teeth, with a little drop in the middle for filing.

I'm not sure I'm picturing what you are describing correctly. If I make the whole bore with the bottom of the nose of the bar, I'll get a much larger bore, since the bar is going through the tree "diagonally" (not sure how to describe what I'm picturing there). I'd get a pretty large bore hole - OK on big trees, but doesn't work so well on smaller ones. I'm used to being able to bore a hole the width of the bar...I just can't do that with the current chain.

John

[beenthere]

John
That is the raker gauge that I use.
When filing the rakers, it seems that there is nothing to file. The file barely touches the raker. I'd assume that was the case with you too (unless there is a way to position that gauge differently).   

Did you file much off each raker?

 

[John Mc]

John
That is the raker gauge that I use.
When filing the rakers, it seems that there is nothing to file. The file barely touches the raker. I'd assume that was the case with you too (unless there is a way to position that gauge differently).   

Did you file much off each raker?

Now that you mention it, there was a bit to file on each raker. More than I usually do, but it had been a while since I did it, so I didn't think anything of it. I put the gauge back on just to check. They all seem pretty close to where they should be... but this is the gauge I keep at home. I'm wondering if the one I use in the field got bent or something. It's possible I may have used my .325 gauge by mistake, but I'd expect that to be a more obvious difference when I double checked just now with my 3/8 gauge.

Oh well... it still cuts great on non-bore cuts, and I've got a lot of buckling to do (a group of friends and I are getting together for our second annual "firewood donation day" this weekend). We do a few cords a year for an anonymous donation to a needy family in our area. Most of the trees are already down, so Saturday is all bucking, splitting and stacking. Maybe I'll use up enough of the chain's life that I can bring myself to throw it out and start fresh.

John Mc

[chainspinrunner]

This could be a lot more simple than you think, next time just try to push down on your saw a little your angle might be off from when you bore in.

[John Mc]

Just came back from dropping a few trees. Used my smaller saw (Jonsered 2152 w/.325 pitch chisel chain). It bore cut just fine, using the same technique I always have. It was freshly sharpened and rakers set using the same style of depth gauge.

My next experiment will be to swap out the chain on my 357 with a brand new one, and see if that makes any difference.

John Mc

[AndyC]

I'm not nearly as capable or experienced as the previous replies you've gotten but I have a Husqvarna 350 that started chattering a few days before one of the two clutch "U" springs broke completely in two pieces.  Probably something else but thought I'd mention it to check into. 

[Frickman]

John Mc,

I'm glad you're getting closer to figuring out the problem. I've been running saws professionaly for decades and I still sometimes can't figure out why the saw is acting up. Put on a different chain and everything is fine. The operator (that's me) just screwed on his filing. It happens, especially if I'm tired or in a hurry.

Kevin,

95% or so of the time I bore when felling I use the top of the nose, not the bottom. Yes, it should kick back on me, that's what the book says. It doesn't. Maybe it's because I've done it thousands upon thousands of times, I don't know, but I have more control and expend less effort using the top of the nose than the bottom.

Now when I bore with the saw in an upright position, like when I'm bucking, I often bore the conventional way using the bottom of the nose. I don't know this method works better for me when bucking than when felling, but it does.

Now don't anybody try boring with the top of the nose at home just because you read about it here. It's just something I've learned to do during a lifetime of running saws, and it works for me.

[Kevin]

There are a few factors that can affect  kick back at the nose when plunging a cut.
The bar nose radius, safety chain, raker height, sharpness and speed of the chain and the boring technique.
I bore with the bottom of the nose to eliminate kick back, that's the only method that is safe to use and it works every time without causing the chatter that John is experiencing.

[GASoline71]

Are you bore cuttin' every tree you fall?  Why?

Gary

[Frickman]

GASoline71,

I bore cut almost every tree I fell. I'd guess 95% of the trees over 10" I bore. The only exception is when I have a back leaner that I know I'm going to wedge over. Even some of them that are bigger I bore cut to set up the hinge. The real small stuff is harder to bore cut and usually I don't have a reason to so I'll just go from the back to the hinge. That's less than 8" on the stump.

The reason I bore cut is to prevent barber chairing. Look around the Forum and you'll see lots of information about that. It also is a more precise method of felling. I can take my time and setup my hinge so that it's perfectly uniform across the width. I then cut back and release the tree. It's hard to setup your hinge when you're racing the falling tree as you're making your back cut.

Kevin,

I'm running Stihl MS460's with the "wide" Stihl 20" bar and 3/8" square tooth full skip, round ground chain. This combination is the smoothest yet fastest cutting combination I have ever run in the woods. Sometimes I run a 24" bar in bigger timber with the same chain. This might have something to do with my ability to bore cut without kick back. I was thinking about it today, and I think some of what I'm doing is using the reactive forces that cause kick back to actually pull the saw into the tree. I know I expend less effort using the top of the nose than using the bottom of the nose.

[John Mc]

...I think some of what I'm doing is using the reactive forces that cause kick back to actually pull the saw into the tree. I know I expend less effort using the top of the nose than using the bottom of the nose.

Wouldn't the top of the nose tend to push you back out, rather than pull you in?

[Frickman]

John MC,

Yes, it will. And no, it won't. It depends on the angles of everything and how you're running the saw. I think that what I'm doing is actually "taming" those reactive forces and directing them to pull the saw into the tree. At least that's what it feels like I'm doing. Where other folks would have the saw kickback on them I have the saw pull itself into the wood. It''s real hard to explain here, it's easier to show you in person.

Several years ago I was logging a property adjacant to where a residential tree service company was doing some removals around a house. I got to talking to them over lunch and they said they had never heard of a bore cut. They said you can't bore the nose of the saw into a tree. After lunch I brought my saw over and bored into a snag they were getting ready to remove. Over and over, again and again I bored into this tree. Maybe twenty times. I used the bottom of the nose and the top of the nose. Not once did the saw kick back. They just stood there amazed. Even the owner of the company couldn't believe it.  I'm not saying this to brag or anything, just that once you learn this skill it will seem a natural thing to do.

Now there's one more little detail that I haven't told you yet. When I bore my back cut, with the saw held horizontally, I'm not going straight in with the bar held parallel to the radius of the tree. I have the saw rotated to the right about 45 degrees or so, I start my bore cut, and then I rotate the saw to the left, clockwise, and then push it into the tree, all in one motion. The angle I hold the saw to the tree to start my cut varies with the tree.

[John Mc]

I think I get what you are describing. When you say "rotated to the right about 45 degrees" you are rotating it toward the top of the nose. I can see how this could help pull your saw into the cut. That's basically what the initial part of a kickback is doing, although more violently and uncontrolled - it pulls the saw harder into the cut. In a kickback, the tooth grabs so hard, it throws the bar out of the cut.

What was confusing me was that I thought you were saying the top of the nose helps pull you through the entire bore cut... which just doesn't make sense to me. I think what you are saying is that it helps you initiate the bore cut.

Neat trick. However, I think I'll stick with initiating it with the bottom of the nose. If my chain grind is just a little off (rakers too low, as I seem to be experiencing now, for example), I'd be more prone to kickback using the top of the bar. Apparently, my sharpening is not consistent enough to count on at this point.

John

[Frickman]

John Mc,

You get the idea of what I do. That's good. It's not for an untrained operator, that's for sure. Like I said before, I've been cutting professionally for decades. I sure didn't start out when I was a youngster bore cutting. It took some time and alot of practice to get onto it. One thing that I learned early on that you're learning now is that you have to have your chain sharpened correctly and a bar in good shape. If you don't bore cutting gets kind of difficult.

I have a rotation set up for my bars and chains. When they're new they go to the woods to fell, limb, and buck timber. As they get some wear on them they're used to trim and buck on the landing and at the mill. At the end of their life cycle I cut up firewood at the mill and trim the occasional dirty log. I do this because I need the greatest amount of accuracy at the stump. As the log travels from the stump to the mill the need for extreme performance of the saw decreases while the accumulated dirt on the log increases, dulling the saw and further hurting performance. When the bars and chains make it to the firewood pile they're pretty well used up and sometimes not cutting all that straight, but it doesn't matter as it's only firewood.

[aldo]

I can't help with the chattering except to say I have a little Husky 142 that I use with a 16 inch Husky bar which has a small radius tip and for some reason it chatters on bore cuts too. I have no idea why but the problem is lessened when I use a new chain, still there but less. My hand filing has never given me any problems before or on any other saw I have. All the other bar tips though are larger radius.

As for bore cuts, I often start with the upper edge of the bar. I just exaggerate the angle initially to pretty much eliminate the chance of kickback. As I create a deep enough pocket I begin to straighten up the saw. Usually it's difficult access, another tree or limb or fence etc in that way. I have never had an issue though. As for doing it for every tree, mainly for heavy leaners or trunk bigger than the bar length.

[Tom]

Hey Aldo, wecome to the forum.

I usually start a bore cut on the bottom edge of the tip and roll the tip into cut such that I'm pushing straight in.  I can't think of anything that would cause chatter but a loose chain, or maybe a dull chain.  I do apply a positive pressure when bore cutting and it seems to go pretty smooth.

Most of my bore cutting is when bucking logs.  Logs laying on the ground that are supported on the ends, will pinch a bar.  I bore cut about a quarter of the way from the top and then cut to the ground.  The "tie" at the top holds the log together and allows the kerf to open rather than pinch.  I then come back and snip the "tie".  That's when the bar might get pinched a bit, but experience will show how thick the tie should be.  If thick enough, the top of the kerf will close and hold the rest of the kerf open, until you meet your original, bored, kerf.

[joe_indi]

Try replacing the rim sprocket, if the saw is running one.
If it has a spur sprocket, have grooves cut deeply into the spur?
If the grooves are deep, this could be the culprit.
A worn nose sprocket  might also be the cause.

Joe

[GASoline71]

S'cuse my being naive... but I really see no sense in bore cutting every tree when fallin'.  Especially trees that are only 10"...

I have been doing this many years... and have some big trees (30" plus over 150' tall) notched in my belt...

I am in no way an expert... but if you have to bore cut every single tree to keep from a "barberchair", then the fallin' technique you are usin' (non bore cuttin') needs to be addressed...  Whether it's just me... I don't know.  Because my intent is to not "call out" or make anybody here feel inferior... but 90% of the people I have come across that use a bore cut to fall every single tree... are making up for lack of proper technique in plain ol' tree fallin'.

That being said... it should be the other way around.  You should be fluent in good/proper fallin' techniques before usin' stuff like bore cuts, "dutchmen" cuts, Coos Bay cuts, and the like...

All in all... be careful... if you contuinue to use bore cuts for every tree... that's your business.  Just don't rely on it to save your butt as the "safe way".  Because it is not.

 

Gary

[Rocky_J]

Gary, take your common sense and get outta here! 

[Al_Smith]

I suppose it's just a different method of doing things . I might have bored half a dozen trees in my lifetime  and they were heavy leaners .

Oh you hear of some who expound on it but usually they are cutting for grade or figure.  Which means very little to 90 percent of us, if we get a little fiber pull on the end of a log ,we just cut it off any way . Much ado over 6 inchs of wood IMO .

[beenthere]

Depends on the tree.

Knowing the technique seems a big benefit, and knowing which trees need the possible extra control one might get from bore cutting, also seems smart (er) in the mix of things. 

I've started bucking a lot of logs for firewood with the method Tom mentioned. Saves sticking a wedge in the cut to keep from pinching the bar.

The speed that some people can cut is another factor. The young guys that move around fast, have plenty of time to steer the tree as it falls. The slower guys like me enjoy the extra time to set the wedges after the bore cut, and nip with a backcut to make it fall.

Almost like everyone can be right. 

[mrcaptainbob]

Between the felling notch and the bore cut, there can't be much left for a strap, considering the width of top-of-chain to bottom-of-chain.

[ErikC]

  I bore a heavy leaner once in a while, but seldom any other time. Bucking logs in the PNW is often done similar to what Tom mentioned, but I think it's a little better way. I start at the top, cut in a few inches, pull back most of the way and drop the bar a couple inches without removing it, bore in, cut out the bottom all the way, then the last piece from the bottom up. Never take the saw out of the log. The log doesn't pinch, and its as fast as it could be. I get a little chatter when boring in once in a while, but usually a little more pressure stops it.

[Maineloggerkid]

I bore-cut trees that need a wedge. It allows me to set the wedge without worry of the tree setting back. If I know its gonna go where I want it, or i can swing it where I want it, I don't bore-cut it. I do find the technique in-valuable though.

I was taught to bore cut with either side of my bar. In some cases I actually prefer boring with the top of my bar. More risky, but it seems to have its place.