"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