bunk or arch – whats the best?

[LostFarmer]

@Carl Russell 23685 wrote:

The problem with steel is that the sled will tend to be too ridged because of the welded joins, which will have some negative effect of the function of the sled. Also the welds will have to withstand a lot of pressure.

Carl

That is true for some but I have one and J-L has a sled that is steel and will flex and move with the the best of the wood ones. The builder has figured out a knuckle that works and works well. But I agree in general a solid sled isn’t good. My grandpa always said a good sled was nearly worn out.

[Carl Russell]

mitchmaine;23702 wrote:

they used to scale hardwood pulp at 5100 lbs. per cord. a cord of wood is about 600′. so 350mbf would weigh in at 2975 lb. at that rate, and when you figure the pulp mills are trying to screw you anyways, sounds like carls estimate is pretty close.

Not saying I’m right….. just basing it on numbers we used when I was a log buyer/scaler….. 2 cords/MBF and 2.5 tons/cd, makes an average weight of most woods at about 10,000 Lbs/ MBF… We used to scale hemlock onto trailers to meet but not exceed road weight limits…. we scaled and weighed and found it to be about 9500#/MBF…. and from a USFS manual I remember red oak being about 11,000#/MBF

325BF x 11 #/BF =3575# ….. So I gave you a few pounds 😀

Really I don’t know what it weighed, but it weighed more than I could roll with a peavey…. and that rarely happens. Truly the actual weight has little to do with it…. The diameter is so great that it had to be lifted off of the ground to skid. I have a cart that could have probably been outfitted with a cradle hitch, but I prefer to use a sled as the log is quite high off of the ground, most of the weight is on the runners, and the log is secure and not flopping or rolling around.

Carl

[near horse]

@Carl Russell 23708 wrote:

Really I don’t know what it weighed, but it weighed more than I could roll with a peavey…. and that rarely happens.
I have a cart that could have probably been outfitted with a cradle hitch, but I prefer to use a sled as the log is quite high off of the ground,…..

Carl

Ya, but Carl, you’re a wood beast! We’re all only mere mortals.

More seriously, and without getting into any astrophysical atom splitting stuff (my head still hurts from the evener thread) – does log length affect the drag? I’m thinking that, as you’re saying with the arch (I think) that too low of an angle drags too much log on the ground, although the front is raised some. The sled can potentially get more of that same log off the ground = less resistance. But, once the log is only supported by the sled upfront and a point on the ground at the back, aren’t we increasing the drag by having it focused all at on small point? Or does the angle with horizontal have to exceed 45degrees before the weight is being transferred back to the tail? I know you can also reduce that drag by moving the log further forward onto the bunk so it’s supporting more but ………

[Scott G]

If you’re interested, this is a good little white paper on conversion issues with scaling methods…

http://www.fpl.fs.fed.us/documnts/fplrp/fplrp611.pdf

For weight it is all about the specific gravity of the individual species and green MC% of the individual tree. That info can be found in the very hefty but valuable Wood Handbook at…

http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100&header_id=p

Best (practical) bet, know what your local & regional species weigh per CF at an average MC% and you’re good to go…

Bug smack lodgepole at 15%MC on a green basis runs ~ 23#CF all day long…

Big green pondo pumpkins that leave a large dent when they hit the ground, upwards of ~70#CF, 45%MC on green basis.

Both grow side by side, but there is a helluva difference when you hitch on to one vs the other.

Take home point; know your wood so you can accurately estimate your loads.

[Carl Russell]

near horse;23713 wrote:

Ya, but Carl, you’re a wood beast! We’re all only mere mortals.

…………

now I kind of think that Taylor Johnson could put a pretty nasty twist on a big piece of wood……:eek:

[near horse]

@Carl Russell 23744 wrote:

now I kind of think that Taylor Johnson could put a pretty nasty twist on a big piece of wood……:eek:

And we see how those “lumberjack competitions” got started!

[Mike Rock]

Carl or anyone,
Is there such an animal as a bunk/two sled runner thingie with a lifting arch built on top of it? I was envisioning something like one delivers propane tanks with. Then when you get the log lifted with the arch/winch you slide or hinge and latch a cross piece under it, like the cross piece on a bunk. Slack off the winch enough to let the log down on the cross piece and bind with a chain. The chain is permanently attached on one side and a boomer/load binder on the other. Throw the chain across and bind it….

???? Or am I delusional again?

Mike

[Tim Harrigan]

@Carl Russell 23708 wrote:

… from a USFS manual I remember red oak being about 11,000#/MBF 325BF x 11 #/BF =3575# …..
Carl

I calculated the volume of that log at 70 cubic ft. Based on my estimates from the USFS red oak goes about 60 lb/cu ft green and 50 lb air dry. So that log would go about 4200 lb green and 3500 dry. Good load.

[Mark Cowdrey]

Mike,
Check out Donn Hewe’s arch-on-skiis:
http://www.draftanimalpower.com/showthread.php?t=2779

Sounds similar to what you are talking about.
Mark

[Mike Rock]

Nice work. That is close to what I had in mind. I was thinking of more work, like a stiff arch with a winch to suck the load up high. If this works, it saves me work! Duh, I just read the part about the arch leaning FORWARD on the load, then standing upright then rearward a bit to lift and stabilize the load!!
Yes, that is much better than a winch!

Thanks Don for doing the hard mental part!

Mike

[Mike Rock]

Nice work. That is close to what I had in mind. I was thinking of more work, like a stiff arch with a winch to suck the load up high. If this works, it saves me work! Duh, I just read the part about the arch leaning FORWARD on the load, then standing upright then rearward a bit to lift and stabilize the load!!
Yes, that is much better than a winch!

Thanks Don for doing the hard mental part. I like the take down version and the stiffness the arch gives. Well done.

Mike

[Mike Rock]

What’s a good width between runners? I also thought of putting the chain that holds the arch a little forward and upward on the tongue base so when the log is pulling the tongue weight is lifted a bit off the neckyoke. Good/bad??

[Rod44]

Here is another way. Back this over the log and lift it up. Then go back over another one and lift it too. These are my Haflinger mares pulling the load when they were staying at my amish friend’s place a few years ago.

http://s716.photobucket.com/albums/ww161/chochocookie/?action=view&current=biglogs008.jpg

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