The snow compacting it, means you don’t have to jump on the pile to crush it. 
Birch breaks down really fast around here, but inoculating and giving it more surface area still helps.
Be thankful you don’t have the vines. I am dealing with a collapsed canopy and it isn’t pretty. I’m hoping the deer and other animals won’t bother with trees planted in the elderberrys.
Oh it’s a sprag clutch, aka one way bearing.
Thanks, I have never heard of that so I had to google it. And yes it is 
We only call it backstop or reverse protection but now I know better, at least for a short while until I forgot what it was actually called 
Test chunking tomorrow?
The plan was to test chunk today 
But yes, tomorrow.
I actually made two thin metal plates as knives today and had one on the upper holder and one on the lower. Testchunked some nettles and that worked like a charm. 
How do you adjust the knifes, since you put so much effort into drilling perfect holes in them? Oval holes in the supports? I freehanded slots in the knifes with the angle grinder. Far from perfect, but adjustable. It’s very important that the tips of the knifes meet, not to make sausage strings of chunks.
Oh, and one more thing. Those are not the knifes we prepared, are they? What kind if steel is that, being so aggrivatin to drill?
Edit: Oh, I forget - nettles??? I never heard of anyone DOW on nettles 
Good questions, and a lot of them 
The supports have threaded holes in them now so no adjustability so far, the knives are 10,95mm too long at the moment so there will be some sensitive work with the angle grinder tomorrow
I’m planning on grinding them to the right measurement with the grinder on a previous pic in the background. To the left of the metal closet there is a grinder and the right green stone on there is the only stone that takes that steel, it is for hard metal and tool steel.
If this doesn’t work I guess it will be slightly oval holes instead with a rotating file (if that works).
No, this is not the knives we prepared, I went for these instead since I think these are more durable. The ones we worked a bit on only has a top layer of something really hard and I believe that layer would break off, the underlayer is regular stainless steel.
I am not entirely sure what steel,it is but I suspect it could be some kind of tool steel.
As I was drilling today I thought that I could also have made regular steel,knives and welded on a bead of hard wear steel and ground that…
Looks great Johan 
When i was into building a rebak i made my knifes from “sacrificial” (?) steel from a road grader, no fun at all to work with, i didn’t make it as long to make holes in them, but i probably would have used plasma cutter/angle-grinder combo
I stumbled over one of my geared motors, so i snapped a pic of the “steel-disc-thing”, as i remember it there should be more stuff, and a sensor- wheel, but it could be some other motor.
Thank you Göran.
I am wondering if that could be some sort of elevator motor, the disc could have brakeshoes on the outside, think train wagon wheel brakes. And the plastic sprocket some sensor probably.
Road grader sacrificial steel, I would imagine that to be something similar (without knowing).
Forgot to write to @JO_Olsson that hopefully there will be no need for sharpening of these knives, therefor I pushed the decision on to the future about adjustability.
Testrun today. I was a bit eager to try so the knives are a little too long so they are now slightly overlapping.
In the end I was saying that the chunks come out 2 - 2 1/2” and the thinner ones up to 3”.
A bit hard to put the plug in while filming
Oh no, only one limb. I wanted to see more 
Congratulations! You just made your first km worth of fuel. Excellent work.
I think you will discover you get slightly shorter chunks as you feed it sturdier limbs.
Thank you.
I’ll make another movie when it is time to actually chunk
Very nice build Johan and in no time at all 
Thank you Göran.
It is a few hours into that build though so I don’t know about that no-time 
It is not complete either, I still need to get the knives to correct length, something to pull it with, a motor protection thingie (motorskydd) (I just want to run it as it should and measure the amperage so I’ll size it right), a shute to guide the chunks onto the drying trailer I made earlier and some protections so noone trips and shoves their arm in there for instance while it is running.
Well, those motorskydd are pretty overrated i think, just like fuses and ground fault interrupters… 
But the safety chute is a good idea, it is not enough to think “it doesn’t happen to me” with these machines…
Hahaha, nobody remembers a coward, as a co-worker would say
This reminds me i need to get a star-delta starter for my axle chunker, i really shouldnt use my “special fuses” …
If you have old circuit breakers (kontaktorer) and a time relay lying around it is pretty easy to build one yourself. I built one for the compressor when I was in school, so it must have been easy, but I don’t remember the specifics from the top of my head now. I would have to read up on it but I am certain that there is loads of info on the interweb.
On my mill I use two separate 3-fase brakers. One wired for star (springloaded/återfjädrande) and one wired for delta. I start up with the springloaded one and when up to speed I just push the next button.
Time delay works good too, but my religion is manual control
Well, yesterday I thought I would get the rebak done so I made the knives the right length, put on a amperage protector, fixed a drawbar and something to use with the hitch on the tractor plus a trailer supportwheel.
Then I aimed for pushing the shear bolt to see how thick aspen could be chunked before the 6mm (1/4”) shear bolt would snap and it was 2 1/4”, about 56mm which is good.
But here’s the problem, shear bolt snapped, so far so good, then the motor did half a turn more and then the axles hooked on to eachother again.
Now, I know that stainless steel is ’dry’ therefor I put in a greasenipple to lubricate where the rebak axle goes through the driving axle (which also is where the shearing bolt is) but that is apparantly not enough.
Could not get the axles to move between themselves and that is when I went inside last night.
This afternoon I tackled the problem and it took me a few hours to get it apart, lots of force applied on the parts to get them to move and the axles now have grooves in them… 
This is where I am at the moment, all I know is that it does not get mounted together with those stainless axles as it was so I will search the web to see other builds and then sleep on it.
My dad said he had seen a build with only one set of rebak knives and they cut against a steel plate under the knives so you still got the ’feeding’ the wood in but does this thing have a name?
Perhaps @KristijanL or @Tone or someone else knows what they are called in Slovenia so I know what to search for since they are mostly used in eastern europe? If one of those even have a name.
