To Hook or not to Hook LG chain?

[Engineeringnerd]

I've been using 3/8 Oregon LG chain on my 372XP w/ 24" bar on some really tough, thick, red oak. The chain often "snags" in the cut, stalling the saw, especially early in the cut even before the bar is buried. It seems unusual to me that it runs better as I get deeper into the cut, but there must be some outside wood dynamics I don't know fully understand. Even in the cut the chain was very jumpy.

In any case, just for fun I took one loop of 72LG84 and ground it to specifications, except I didn't put the "hook" in it. In other words I ground it @ 60 degrees, 25degrees , and 0 degrees (instead of 10 degrees to form the hook). If I use my imagination, it may have cut slightly slower while the cutters were turning, but the saw ran much smoother and the the overall cut was significantly faster since I wasn't having to back the saw out. The chain also seemed to stay sharp much longer. I was able to make several deep plunge cuts and base cuts on the stump. I also made a number of rip cuts on 20-22" diameters logs make rough planks for benches, and cut a bunch of 3" thick cookies of same to make stepping stone for the wife's garden. Chain was still sharp whereas my standard LG with the hook lasted half as long in similar territory before petering out (no dirt hit).

2 questions for my friends on the forum:

1. Any input on the pro's & con's of loosing the "hook" on chisel chain by grinding @ zero degrees?

2. What do you see as the pro's of a 25 degree top plate angle versus say a 35 degree angle?

 

[SawTroll]

Stihl specs call for zero degrees for the RS/RSC etc - maybe there is a good reason for it??????

I file my Oregon LP chains at close to zero degrees also, and is quite happy with the results.

 

[Timberhauler]

LG chain is my only choice,I by it by the roll,and use at least a roll a month.I quit measuring exact angles years ago,but the drags on that chain when it is new give the cutter a little too much bite,plus I have found that it pays to go ahead and sharpen in before you run it,the factory edge is not quite as good as what I can do by hand.Red oak seems to snag my chain from time to time no matter what,so I just hole the saw back lightly until I get into the cut and the saw hits full power.It's hard for me to explain without showing,but when I get out a new chain,I file out the excess metal under the tooth,then I round the top of the drag slightly.I file at a deeper angle that the service mark on the tooth.It seems to cut much faster.

 

[Patrick62]

With the stuff that I sharpen I tend to sharpen 3/8 chain straight across, and the .325 with the 10 deg "hook". The smaller chain seems to work pretty well that way, but the 3/8 worked better (for me, anyway) level.

your mileage may vary.

-Pat

 

[Engineeringnerd]

Thanks for the input guys, maybe I'm not going insane after all.

All I know is that the factory LG "grabs" way too much when new. Good to know others have the same issue.

Timberhauler, I appreciate your response because I have noticed LG gets better as the chain wears as you noted. It maybe due to the more careful grinding I do and/or because the tooth gets smaller towards the back and causes less drag.

I'll probably continue with the level grind from this point forward.

 

[bwalker]

The percentage of the file thats under the top plate is what really control the amount of hook. I have never had a problem with 72 LG being grabby off the roll. It will get grabby if your file is riding to low on the tooth.
I chain with alot of hook will cut like greased lightning through softwoods like jack pine and aspen though.

 

[B_Turner]

I've always found my 371 and 372's I've borrowed a tiny big grabby on certain tough woods. A number of times (like with black locust) I've noticed this slight grabbiness and switched the same chain over to a 460 or sometimes even a slightly small Stihl and it was noticeably less "grabby." Even on new chain (not just LG) including square.

Dolmar is like the Stihl in that I don't get this grabbiness.

I really don't understand it, and it is the only thing about my 371 that I would have different. I thought maybe the long dogs were changing the angle the wood was being grabbed, but putting shorter dogs on the 371 made no diffference.

Same chain on a 440 or 460 and less grab (same wood). I probably sound crazy, but I've repeated the same results many times over the last several years. Not a big deal in wood heavy enough to stay put, but I really would have liked to understand why. Since the clutch is locked up during the cut, it doesn't make sense to me.

I've had other people try each setup, and they agreed the 371/2s seemed grabbier than whichever Stihl I threw the same chain on. Really weird. And in fact my 395 is a tiny bit grabbier in certain situations than my 066 (again, literally same chain).

 

[SawTroll]

The percentage of the file thats under the top plate is what really control the amount of hook. ....

That is a good point, you sure are right.......


... but it doesn't explain what b_turner said

 

[Bowtie]

I have the same problem with Carlton chain that I tried on my 034 av. Used stihl on the 026 and didnt have that problem. Im gonna try a stihl chain on the 034 in the same wood, see what happens. I suspect that I should have stuck with stihl chain like my signature says. :deadhorse:

 

[PES+]

If you do not grind or file what I call the "back angle" on a full chisel I find that you need to lower the rakers a bit in order to keep feed speed up. I never will grind FC to 0 but I do sometimes lower it to 5 degrees and then increase the top plate angle a bit.
The full 10 degrees I find puts too much out cut grab in certain woods and causes a chatter in really hard or gnarly woods.

 

[RaisedByWolves]

The percentage of the file thats under the top plate is what really control the amount of hook. I have never had a problem with 72 LG being grabby off the roll. It will get grabby if your file is riding to low on the tooth.

Agreed!



When I first got my File-n-joint I got a lil careless and set the file too low, cut up some poplar just fine. (35* with 10*)



Then I tried to cut a Red Oak stump for use as a chopping block. The saw was so grabby it was nearly jerking out of my hands very violent experiance (I was afraid I was going to break the case!) so I quit while I still had hands and looked over the chain.



The chain now had Summer Teeth! I couldnt believe how abused looking it was, but I did realize my mistake right away.

 

[trimmmed]

I've always found my 371 and 372's I've borrowed a tiny big grabby on certain tough woods. A number of times (like with black locust) I've noticed this slight grabbiness and switched the same chain over to a 460 or sometimes even a slightly small Stihl and it was noticeably less "grabby." Even on new chain (not just LG) including square.

Dolmar is like the Stihl in that I don't get this grabbiness.

I really don't understand it, and it is the only thing about my 371 that I would have different. I thought maybe the long dogs were changing the angle the wood was being grabbed, but putting shorter dogs on the 371 made no diffference.

Same chain on a 440 or 460 and less grab (same wood). I probably sound crazy, but I've repeated the same results many times over the last several years. Not a big deal in wood heavy enough to stay put, but I really would have liked to understand why. Since the clutch is locked up during the cut, it doesn't make sense to me.

Me either, based on the chain swapping you are concluding that the saw itself is grabbier.

... but it doesn't explain what b_turner said

Troll is your 372 "grabby" ?

 

[PES+]

I've always found my 371 and 372's I've borrowed a tiny big grabby on certain tough woods. A number of times (like with black locust) I've noticed this slight grabbiness and switched the same chain over to a 460 or sometimes even a slightly small Stihl and it was noticeably less "grabby." Even on new chain (not just LG) including square.

Dolmar is like the Stihl in that I don't get this grabbiness.

I really don't understand it, and it is the only thing about my 371 that I would have different. I thought maybe the long dogs were changing the angle the wood was being grabbed, but putting shorter dogs on the 371 made no diffference.

Same chain on a 440 or 460 and less grab (same wood). I probably sound crazy, but I've repeated the same results many times over the last several years. Not a big deal in wood heavy enough to stay put, but I really would have liked to understand why. Since the clutch is locked up during the cut, it doesn't make sense to me.

I've had other people try each setup, and they agreed the 371/2s seemed grabbier than whichever Stihl I threw the same chain on. Really weird. And in fact my 395 is a tiny bit grabbier in certain situations than my 066 (again, literally same chain).

You may be feeling the differences in the clutch construction and spring tension. Have you swapped bars between the Husky and the Dolmar to see if it could be a bar difference?

Wait a minute....I bet you are feeling the differences in the way the AV mounts react and I know what you mean the 371/372 springs are longer than most and whip a bit....hard to explain

 

[trimmmed]

I use LP and LG almost entirely, I usually run the chain as it comes of the roll. I can't say I really felt or noticed any grabbiness. What I was finding was when I go to file that chain for the first time, (after using it first) is that the rakers are not all of equal height. So I spun a loop and checked it before use, and found the same thing. This is using a file-o-plate, hardly a scientific experiment, or instrument, but I believe the results.
Anyway, I say keep the hook and the 25 degree angle until you have fine tuned your rakers. I am real happy with LP/LG at the factory recommended angles.

 

[SawTroll]

The rakers on rthe H42/73LP chains that came with my 372 was far too high - needed about 5 to 7 strokes with a raker file to get tham right........

 

[B_Turner]

You may be feeling the differences in the clutch construction and spring tension. Have you swapped bars between the Husky and the Dolmar to see if it could be a bar difference?

I do swap bars between the husky and dolmar and no change.

I probably should have kept it to myself as I figured I'd get some eye rolling. But I've duplicated the slight grabbiness of the 371/2s in certain tough woods like black locust alot of times. Not noticable with most cutting I do, but occasionally pretty noticeable.

I switch the exact chain over to say a stihl to make sure it is not the chain itself that is the culprit.

I have sort of figured it was a clutch thing, but since the clutch was locked up at rpm it didn't make sense.

Is of course worse with certain grabbier setups like extra hook or skip chains. And again, it's only noticeable in certain fairly extreme conditions. I've heard a similar observation from other turners as we are constantly cutting wood in non standard grain directions, and in fact Stihl are general the saw of choice with woodturners.

So maybe with my original post I should be like Homer, "did I say that out loud?" But I think it's true...Also want to add I've cut ALOT of wood with my 371 and it's been a great saw.

To try to create a distraction, here is one of my "skeleton bowls" from my "Bones of the Tree" series.

 

[Engineeringnerd]

Well, just to be clear, when I used the new LG on a 24" bar with the 372 it grabbed and stalled quite frequently. Realize this was a really tough, large oak that had been dead for 6 - 12 months, though sap was still in the trunk. I could keep the chain from grabbing and stalling the saw by rocking the bar slightly in the cut to prevent a large flat area in the cut. Sometimes I would hit sections where the bar would start pulsating and jumping. Once I took the hook out of the chain it was smooth sailing and I could even lean into the spikes a bit.

I think its a combination of three things; 1) the wood I was cutting was extremely hard, 2) 24" in that kind of wood is pretty hard on a 70cc saw, 3) LG is aggressive chain, probably best suited for softer fare or a larger saw for lumber this size.

Changing any of the three variables would probably help the situation. Given I don't have a larger saw and I often cut such oaks, taking the hook out seems to be the ticket for me. I don't carry a stopwatch with me in the woods, so an extra second or two in the cut really doesn't matter.

 

[bwalker]

My stock 372 will burry a "24 bar all day long in Sugar Maple or White Oak, which is much denser than anything you got in the south.

 

[Kneejerk Bombas]

To try to create a distraction, here is one of my "skeleton bowls" from my "Bones of the Tree" series.

Awesome bowl!

 

[Engineeringnerd]

BWalker,

Once I ground the LG flat, I buried the 24" bar with a bore cut into the stump which was 49" x 39" and worked my way all the way around the stump. The tree had two trunks joined at 6' off ground, I was cutting @ 2' off the ground. I ended up making two cuts to create a 4" thick slab to make a tabletop for my daughter. Very nasty stuff with knots and all kinds of crazy grain where the trunks came together. I've never cut sugar maple, but this was the match for any white oak I've ever cut.

Here's a little additional info. I ripped several clear logs of the same tree without incident that were 20 - 22" in diameter to create thick slabs about 2' long. I ripped some from top to bottom (The log standing up) and ripped some from the side (log laying down) from bark to bark. Also I'm on about my 8th tank of gas.

What kind of chain and angles do you run on your 24" stock 372 to get best performance?

Is there a practical way you know of to objectively measure a saws performance to be sure its making its full potential?