Understanding wood fiber -theory.

[davidwyby]

Fiber pull has more to do with hinge thickness.

I think it contributes. The front compression half of a thick hinge could act as a fulcrum to pull the rear half tension fibers. I think it has more to do with whether the face closes before the hinge breaks or not. If the face closes, the log become a claw hammer pulling a nail (right drawing). It’s almost standard, automatic for a western cutter to trim the pull off the stump after felling, not necessarily just because it’s a Humboldt, but because they tend to end up deeper and more closed.




If the hinge bends until broken, it pulls down into the stump, instead of out of the log (left drawing). This is why eastern cutters make vertical hinge walls.







Back to the ‘chairing topic, the flare trim face and bore cut keep the whole rigid log together and eliminates fractures.

My bone to pick with eastern cutting is the short bars and the requisite dancing around the tree. All this boring and stuff is also tedious and I think simply not worth it for western timber.

 

[davidwyby]

True. Sawmillers say to avoid the pith as it splits and quite often trees I cut are already cracked there. So to avoid a chair we need to get deeper in past the pith. That’s the tricky part. I have an idea for bore cutting out the face and leaving a collapsible kickstand in the front, but it’s very gimmicky and at that point one would be better off to just bore and trigger.

Then again, if we bore the pith out…OTOH, the grain running opposite the hinge will resist bending and maybe increase the chance of chairing.

So deep face prevents chairing but you gotta sink it into the rear third! 😆

 

[SeanKroll]

How much barberchairing do you run into?


Only a few species here, aside from loaded trees (e.g. felling a support tree holding a tipped tree) want to BC.



Thick hinge... lots of fiber pull. Undesireable for butt logs at the mill...$ deduction, to my understanding.


If I'm trying to hold a side lean, I'm looking to end up with a lot of fiber pull/ whiskers.





Side note: backchaining whiskers is SOP.

One- eye Guy was bottom-barring 'whiskers' and flung a whisker past his 'safety squint" into his eye. It got infected and he lost an eye.


No thank you!

 

[davidwyby]

How much barberchairing do you run into?

Little to none. It’s just not a thing with my short interlocking grain (also usually dead and resin baked brittle) trees. I could probably no face and normal back cut head leaners with no issue. Only time I can think of a chair was a salt cedar sapling years ago when I did it on purpose just to see.

Only a few species here, aside from loaded trees (e.g. felling a support tree holding a tipped tree) want to BC.

I just see it or potential for it in the many online communities I frequent where they are back east and dealing with EAB.

Thick hinge... lots of fiber pull. Undesireable for butt logs at the mill...$ deduction, to my understanding.

Yes, but seemingly less so in the west than the east. Fiber pull could ruin a veneer log if it makes it too short to get a full width peel methinks.

If I'm trying to hold a side lean, I'm looking to end up with a lot of fiber pull/ whiskers.


Yeah. Recent Mesquite side lean tapered hinge pulled with big tractor, pulled a huge chunk out of a nice log. :-(

Side note: backchaining whiskers is SOP.

One- eye Guy was bottom-barring 'whiskers' and flung a whisker past his 'safety squint" into his eye. It got infected and he lost an eye.


No thank you!

Makes a lot of sense. I have noticed myself back chaining such things.



Similar:

Recently I read somewhere something that made me smack my forehead. Cutting brush near the tip, back chaining greatly reduces thrown chains. As the bar passes thru the stick, the chain has already gone around the end of the bar and is much less likely to derail. Duh. Also throws junk away from you instead of towards.