Saw Pinch

[mdtreeman]

I was bucking 30 inch logs today using a Stihl 461 with a 20 inch bar. When I made my initial cut, the saw cut really well; however, as my saw buried further into the wood and I rotated the tip of the bar inward towards the pith of the tree, it felt like the saw was pinching near the tip of the bar. The cuts are straight but it felt like there was some sort of binding. I made multiple cuts and it happened every cut. So it’s not the pressure from one end of the log being in the air or the log bridging. The log was completely flat on the ground. It appears to be a chainsaw issue. My question is, is it the chain or the bar, or a combo of the both? And while I’m asking. As I said the cuts were straight, but are crooked cuts the result of the chain or bar too? I feel like I can fix a dull chain but when this pinching stuff happens or crooked cuts happen, I’m not sure how to fix that. Can get very frustrating and time consuming. Thanks

 

[BobL]

Are you using ripping chain. The 10º top plate filing angle can sometimes bind a bar when used in cross cutting. It depends on how much wood fibre tear out occurs, with the torn fibres dangling in the kerf. Thats why 25-35º angles are used for cross cutting chains.

The following will bind the bar but also usually produce curved cuts
Unequal length eft hand and right hand cutters - file accordingly. Strictly speaking the cutter and raker angles have to be the same otherwise the cutters will grab different different amounts of wood.
Uneven bar rail wear will tilt the chain on the bar rails - dress bar and if the chain is worn beyond recovery replace it
Not common, but still common enough is the mismatching of gauge chain/bar , eg using a 0.058 chain in a 0.063" bar

 

[Marine5068]

Are you using ripping chain. The 10º top plate filing angle can sometimes bind a bar when used in cross cutting. It depends on how much wood fibre tear out occurs, with the torn fibres dangling in the kerf. Thats why 25-35º angles are used for cross cutting chains.

The following will bind the bar but also usually produce curved cuts
Unequal length eft hand and right hand cutters - file accordingly. Strictly speaking the cutter and raker angles have to be the same otherwise the cutters will grab different different amounts of wood.
Uneven bar rail wear will tilt the chain on the bar rails - dress bar and if the chain is worn beyond recovery replace it
Not common, but still common enough is the mismatching of gauge chain/bar , eg using a 0.058 chain in a 0.063" bar

I always like your good, practical advice and experience Bob.
.

 

[Marine5068]

Are you using ripping chain. The 10º top plate filing angle can sometimes bind a bar when used in cross cutting. It depends on how much wood fibre tear out occurs, with the torn fibres dangling in the kerf. Thats why 25-35º angles are used for cross cutting chains.

The following will bind the bar but also usually produce curved cuts
Unequal length eft hand and right hand cutters - file accordingly. Strictly speaking the cutter and raker angles have to be the same otherwise the cutters will grab different different amounts of wood.
Uneven bar rail wear will tilt the chain on the bar rails - dress bar and if the chain is worn beyond recovery replace it
Not common, but still common enough is the mismatching of gauge chain/bar , eg using a 0.058 chain in a 0.063" bar

I hope you don't mind, but I always point greenhorns from other sites to come read your milling advice and learn from you.
I guess you could say you're my milling GURU.

 

[BobL]

I hope you don't mind, but I always point greenhorns from other sites to come read your milling advice and learn from you.
I guess you could say you're my milling GURU.

Cheers,
FWIW I do date same thing. I post fairly often on an Aussie wood workers forum and they have a small timber milling section where milling questions come up all the time. I post a lot of the same stuff I post here on the woodworkers but occasionally to save repeating myself I often refer them to AS.