Ox logging and ground skidding draft measurement video

[Andy Carson]

@Tim Harrigan 28162 wrote:

I have thought about changing the surface material but not the shape of the runners. You rockered the runners, but you also seemed to describe a natural process of wear whereby the runners took on a rockered profile. So do the runners seek a low-draft profile? Are you suggesting we need to be more attentive to the shape of worn runners when we replace them with new runners? That makes sense to me.

i hadn’t really thougth of watching the runner wear as a practical tool, but yes, that would definately be a good idea. An ideal runner would wear evenly over the entire contact surface. If one notices that an area wears more than any other, that area should be smoothed or back off whenever the runners are replaced. You know, not only would that reduce the force required to move the sled, but also would save on steel… That’s a great thought!

I would be curious about the results of pulling different weights over the same surface too. The compressibility of the soil has been a difficult thing for me to model completely, because soil behavior seems to vary alot by soil type and moisture content. Not only is the compressiblity variable, but also the dampening effect varies. At very high dampening rates, one might see a reduction in the apparent friction coefficient at high weights, because the soil doesn’t have time to compress fully during the time the sled is acting on it. I really don’t know if the dampening effect is significacnt in something like a pulling contest. There are just so many unknown and important variables in this analysis that even I won’t hazard a guess.

[dominiquer60]

It may be Andy’s fault, but you are an enabler Tim:)
I follow the ideas just fine, but the math makes my head spin, if I had not been dating Good Will Hunting when I was at college I would have never made it through the course that they made me take. My comfort level doesn’t go past the Pythagorean theorem at this point, it is good to know people that exceed my meager skills. Like I said, I am enjoying every bit of nerdiness. Rock on!

[Tim Harrigan]

@dominiquer60 28165 wrote:

It may be Andy’s fault, but you are an enabler Tim:)

Maybe, but he makes it so easy.:cool: He has two farm dogs, Pythagorus and Isosceles. 😉

[Baystatetom]

The math is to much for my small mind as well, I think I’ll just keep hooking onto things and pulling them without worrying about anything but how hard it looks like my bulls are working.
I did however just break my yoke by hooking a rock with the corner of my stonebolt with a load on. The team felt it hit and jerked it loose, I heard a big crack and that was all she wrote. Ever catch something like that on your draft meter? Must have been a lot of force there to break a 7″ yellow birch yoke.
~Tom

[fabian]

up to know I thought that the bows are the weakest points of a yoke….

[dominiquer60]

That may depend on the yoke and bows that you are using. I broke a yoke plowing last fall, I heard a weird noise and then we hit a rock, snap. It makes sense that the yoke is the weak point, the bows are only supposed to hold the yoke in place. Mine broke between the staple and the inside near bow. The guy on the plow panicked because my steer was loose, I retrieved him from the 10′ that he walked forward and hitched my belt between his bow and the ring and they walked back to the trailer unscathed. I like horses but moments like that make me appreciate cattle more.

[fabian]

@dominiquer60 28218 wrote:

the bows are only supposed to hold the yoke in place.

I think that this is not totally correct.
If the bows were only supposed to hold the yoke in place they could be made from material which is easier to bend than hardwood. At the Tiller’s site I found a statement that the yoke does 2/3 of the work, the bows 1/3.

[mitchmaine]

to be fair, fabian, cause tillers says something does that make it so????? the first thought i had was why does a 2″peice of round stock cranked around 180 degrees under wicked strain performing twice the work that a 5 or six inch straight grained log? that doesn’t make sense especially when some yokes don’t even require bows. no disrespect to tillers but i’d have to hear some more talk on the matter.

[fabian]

A friend who logs with a single ox first cracked the bows I gave him. Then he used an iron bow. Finally he cracked the yoke.

I trust in Tiller’s and in Drew Conroy 😉
Which yokes do not require bows ? The wither’s yokes ?
They mostly do not have a dropped hitchpoint. The deeper the drop of the hitchpoint, the more power the bow has to catch. So I learned it and so I believe it . 🙂

[mitchmaine]

perhaps the bow is the weaklink, wittingly or unwittingly designed into the system to fail and protect the yoke from snapping. alot easier to bend a bow than shape a yoke.
seems to me the yoke is trying hard as it can under a load to stay on the same plane as the chain, fairly horizontal with the beasts shoulders and necks under the yoke and when the rock and hardplace converge, and something has to give and it ain’t gonna be the chain……….

[dominiquer60]

I stand corrected “the bows are mostly supposed to hold the yoke in place.” The three yokes that I know of that have broken all had sound bows coming out of the malfunction of the yoke. I can see where the bows can be stressed or pushed against, from my limited experience it seems that it would take a bad bow or an unusual situation to break a bow. I am not saying that the bow that Wolfgang made for his friend was bad, just saying that a bad bow is a possibility of a situation in which a bow may break.

[fabian]

@dominiquer60 28233 wrote:

I am not saying that the bow that Wolfgang made for his friend was bad

The bow WAS bad !:o

It was to weak for this job because it was made from Rattan, which is strong enough for pulling my waggon or cart.

Wolfgang

[Baystatetom]

I know of several broken yokes just in the small circle of friends I have with oxen. Of course they are all into ox draws and hook to loads you would never ask of a working team.
I agree most of the force should be on the yoke, but you can see when a team is really lugging hard on a heavy load that the bows sink in between the shoulders and the neck. They have to be absorbing at least some of the load. But it should be the sides or vertical parts of the bow not the bent bottom.
The other thing not to forget is anything that can go wrong will go wrong
~Tom

[Vicki]

I saw a bow break during a heavy-class ox pull at Fryeburg, ME. An exciting moment. Wonderfully, calmly, skillfully handled by the driver who was Brian Patten if I recall.

[Tim Harrigan]

[Author]

Posts