Home Made Log Chomper Crashes And Burns! 

Now that's an impressive failure! What a sturdy gearbox that must be. I think you could do with shorter blades so there isn't so much leverage reacting back on the shaft. Really I think you might consider a hydraulic ram, a simple wood splitter modified with a guillotine style shear on the end. That seems a more reasonable way to get the kind of force you're looking for with perhaps foot pedal actuation. I'm sure the gearbox wouldn't go to waste as you'd quickly find something else to do with it. This made for an excellent video in any case!

The blade really is too long, plus it's on a wide hub. You're cutting nearly half a meter from the point of rotation. You should be cutting as close to the axle as possible for maximum torque.

Now that's a widdow maker! Well done. Keep your fingies out of it!

That's the most frightening machine I've ever seen, fantastic!

One of my all-time favourite videos. It has an excavator, concrete being poured and a very large and sharp spinning blade. What could possibly go wrong. Just glad everyone is safe and look forward to the next installment.

Great project Tim! Perhaps you could guide the whole blade within a circular guard casing around the tip of the blade. I feel that a flat bed for resting the branches on could help in shoving them forward. A guard around most of the blades could help you with 19th century safety (and one for the engine shaft too!)

Perhaps a shear pin or a brass key would help if you want to continue to use the gear reduction? That way it would fail in a safe and easy to fix kind of way.

Take care. That machine doesn't know the difference between arms and logs. A slip clutch or shear pin might be a good idea. An emergency stop for the engine ? Some farm machinery have spring loaded clutches. The PTO on a small old fashioned baler comes to mind. I think your place of cutting should be moved nearer the centre of the chomper. More cutting force and more overlap for the blades in the slot.

Two classes of things are clearly needed: 1. An obvious, safe, planned way for the machine to safely disengage when the inevitable un-choppable object is inserted. 2. A WHOLE BUNCH of safety guards! Think about all the different ways that human fingers, arms, etc., might encounter those blades, belts, shafts, and any other moving parts (or even sharp non-moving parts!).

Just what we love to watch .My husband love’s to what you are up to Tim .We haven’t had a good day lovely to unwind with you .Best regards we love Ireland as well.Happy St Patrick Day to you both.Good luck 🍀.🧚🧚☘️☘️☘️🍀🍀🍀🇮🇪🇮🇪🇮🇪🇮🇪

"...tragic, interesting, and amusing." Yeah I'd have to agree with that one. Thanks so much for the smiles and even chuckles, in these trying times.

Very good, Tim! Never give up, never surrender! Perseverance!

An unexpected education comes from all angles ... or indeed revolutions. Thanks for the honest entertainment 😃

Love this channel. That contraption looks like it could maim you 42 different ways. Stay safe out there and good luck with the railway!

I absolutely love seeing your whole process including the failures and improvements. You could just release 10 second videos titled ‘easy peasy’ but showing the whole journey is *so much* more valuable and real. Thank you!

Me seeing the notification to this video: "Let's go!" Me when i read the title: "Wait- what?!" There has been built a ballast truck, 5 wood trucks for wood, even a log chopper and a boiler, that's amazing.

"Never fear!" he says, as I'm clenching my teeth through the whole video! Stay safe, Tim!

You have no idea how much I enjoy watching these videos - nevertheless that I don’t understand the first thing about it

@7:50 - I almost watched the later video when you rebuilt this, but I am glad I paused that one to come find this one. In my head, I pictured this thing wailing and gnashing away at a fevered pitch. Instead, I am pleased to see a contrivance of quiet, unrelenting power that is hypnotic to watch. I think I shall subscribe to your channel, sir. Well done.

Wowee! What a great illustration of the forces you were wondering about!

It's like watching the industrial revolution Tim, make a tool to improve another tool, cheers.

It all one big test , big thanks for posting all your lessons

Hurrah! Thank-you! From Littlehampton, West Sussex. Marvellous videos!

That's the spirit, never give up! (But stay safe, I don't fancy watching an amputation.)

the power of the engine is amazing

Loved the updates at the beginning. Very nice concrete

When it was working it was soooo satisfying to watch.

one man's quest to build the most dangerous machine in all of Ireland

There was a distinct lack of burning in this video. I came here for a disaster! Really satisfying to see the blade just slowly slice straight through those branches.

I think what you need isn't knife blades, but a saw blade. Shape it with an expanding radius like your knives, but allow it to take only one bite per revolution. Shape the teeth with deep gullets so they have room to hold all the chips generated by the tooth's passage through the log until they get clear, with alternating peaks on the teeth to reduce the load on each. That is one hell of a gearbox.

That was satisfying to see it chop through those willows like a hot knife through butter--until the end. :)

Bandsaw frames like that are priceless around here. I'm happy for you that you found one. I'm grateful for your videos.

You blokes are great. Such great self reliance

Seeing how mangled it got really shows you how much power you had to work with, looks like it would've gone through a whole tree if you could fit it in! For your next iteration, and I'm sure you already worked it out after your experience, you may want to look into adding some sacrificial parts that will fail before something like that is able to happen 😱

You'll figure it out, and make it work. I admire your tenacity, as well as your ingenuity!

Perhaps a new site address of 'Danger Man' might be in order. Exciting stuff. I admire your patience and persistence. Keep it up, Tim.

Very exciting as usual. Two ideas: 1* blades should be attached to flywheel, to reduce load to gearbox, shaft and frame. Due low speed, the flywheel needs to be very heavy of course. Perhaps a truck flywheel/clutch assembly would work. Could use the clutch to disengage the blades too. 2* cutting disk could be coupled to shaft via impact driver style clutch. You know the spring loaded spiral thingy. It would prevent excessive loads to components when blade gets stuck and would hammer through the bigger branches.

Very entertaining. It is potentially a winner, just a few more hurdles.

Every time that blade makes a turn my inner safety officer has a heart attack

Great machine. Think you may need to "up" your liability insurance though! 😄

I love how you run counter to ever increasing health and safety requirements. Seems that each project becomes more lethal than the last. I'm astonished at the diameters it could slice through though: the stresses must be enormous!

In Engineering we have a saying "Failure is NOT an option! It's a topic," We design in places where 'Low Cost easily replace' parts blow up before sometihing dangerous/expensive breaks.

Always a fun adventure on this channel. Still my all time favorite tinkerer...(all we need now is a tailor, soldier and a spy) :)

I Hope this does not all end in tears

I love watching your vedios and can't wait to see more railway and more steam progress vedio.

Fantastic ingenuity

Great project! I always love videos like this where one analyses mistakes made so we can all learn. I am also glad to hear the gearbox is fine. Some stuff I have noticed from watching tons of these wood chunker videos online and attempting to build one for myself: - Blades that have only a single cut, tend to perform best. Chunkers like yours that have two cuts seem to put more pressure in a shorter span of time. Maybe try a single, spiral blade next? - Cuts made at a right angle to the wood are harder. Imagine chopping a tree by chopping ONLY at right angles. That's hard because it goes against the wood fibers. Try setting up the blade so that the wood will be cut at a diagonal across the wood. Really great progress though! This is such a beautiful setup you have there and I am completely convinced you will get there! Edit: and as others have mentioned some kind of mechanical fuse / sheer pin might be in order. I am planning to put one on my chunker as well. Shaft comes out the reducer, has a hole drilled into it. Over this shaft fits another, much bigger shaft with a hole in that one too. This last shaft connects to the blade. Then I'd place a tractor sheerpin into the two holes connecting the shafts. Should a similar situation happen again as in this video, you don't run the risk of ruining the gearbox.

Classic illustration of the old saw "There's a reason we have engineers"

You're using about 30 degrees of rotation per cut, make a blade that takes 180 degrees to cut, spread the load/work over more time and move them towards the centre like other people have said

As crashes-and-burns go, that was rather impressive! :)

jesus these forces are astronomical! but it's fantastic that you made it work that well even if there was a lot of trial and error

This is how the Panama Canal was built. They admitted that they did not know to do it, so they said " do something, and correct the mistakes."

Great determination, as always!

Your videos are a welcome diversion. I love that you just get an idea, and build it. Reminds me of how I used to think anything was possible when I was a child.

Very interesting and entertaining too!👍☘️

I believe that’s called “testing to destruction!”

I'm going to build one of these. I've dreamed of having one of these all my life!

O boy! it was exciting!

You might consider a single shear pin in the system. Perhaps holding a drive plate attached to the gearbox, to a blade plate attached to the blades. You can make your own shear pins by grinding a bit of a notch in a bolt where the two plates would slip if the bolt was not installed. On my brush hog, the shear pin is a single grade 8 bolt, but that's a bit unusual usage of a bolt, normally they are special bolts designed specifically as shear pins. It does however do a great job of snapping off when I mow over a stump or something big. Lots of stuff about shear pins online regarding snow blowers, including lots of home made shear pins from bolts etc, so it should be easy to research if you go this direction.

Great vid. Thank u. Best of luck with Mark 2.

If you cut closer to the shaft mechanical advantage would be on your side and the blade would be in the slot and less chance of twisting or bending. A shear pin on the blade will let the blade flop back. A greater angle will cut slower and be an advantage.

But you are able to laugh about it... love you guys

When making it again, consider a hard brass or soft steel for the key. It's an easy part to replace, and you want it to fail first.

A Victorian "maiming machine " Love it!

Bigger and stronger than before….. and safer too, I hope! Had me on the edge of my seat!!

Tim: *_"...and no one was watching so it went fine."_* And if it hadn't I'm sure the video would have disappeared...🤭

Yet another brilliant video, thank you. 😊

What an incredibly strong & capable machine you've built, it definatley had an impressive break.

What a shame. I look forward to the next revision!

I see many others saying to cut closer to the shaft for better leverage, but I also suggest that the blade be designed such that it begins to slice the logs at a more oblique angle. It will start the cut easier and once the cut starts, it is easier for it to keep going. Good luck! 👍😉

hence why engineers include specific failure points to protect the expensive stuff while replacing a cheap stuff becomes barely a hassle

Very good! The next is sure to be better

That chomper has all the hallmarks of a limb remover, take extra care when using!

I just caught up Tim! I like how you bring so many friends into your work. The best part was when it was time for tea with Tim and Will.

interesting... the forces must be very large....good project

Great video.. Thanks for sharing

there's the first impression right there Tim digger

Wow! 84 to 1, that's quite a special gearbox. It would be one hell of a start on making a dividing head

Absolutely fantastic outro monologue there

It makes a really satisfying chomping noise!

Judging from the sparks off that key, it was high carbon steel---probably was fairly hard, judging from the damage. See if you can get something softer. McMaster (in the US) sells machine keys that are Rockwell B 50 or 100. The B scale is so soft it is tested with a ball bearing, not a diamond point.

The two pieces of angle iron that the blade runs between can be arranged even closer and in such a way that they prevent the blades from bending sideways. Should do the trick. Then it's on to the next failure point.

Old square baler gearboxes are pretty sturdy.

Oh my God. That rotary guillotine gives me nightmares. No safety shut off, no safety shield, no emergency stop. Just one slide away from a deadly slip up. Lucky it killed itself first.

A flat belt would work better than a V belt, they slip/clutch better than V belts. Thinking about it you really need a jackshaft with fixed and loose pulleys & a shifting fork, that would be the only real safe/effective way to run such a setup. I can research it if you like but I think they can both be flat, not crowned. Your buddy with the lathe can crown them if not. A disc brake would be a good idea as well. Keep an eye out for crowned pulleys at flea markets/rummage sales, there are lots of the out there. Cheers.

my ideas, remove the slot for the blades or make the slots wider, also add a safety coupling with a shear pin that is going to snap in half and stop the machine from destroying itself in case the machine jammes again

The end speech... It reminded me of Emperor Palpatine declaring First Galactic Empire in Senate.

Have a look at some of the Yanky You Tube log chompers and you will see that they use a wheel with the rim cut into a cam shape and sharpened all the way round, which give continuous progressive cutting with the log being fed in on a slightly slanted flat plate so after a cut the log is slid down to a stop for the length required and the cutting action begins.

Well it's a damn shame. Might be worth trying to propagate that particular chunk of branch. It is apparently a very hard wood!

My two pence worth, your problem issue is the blade design. The blades need to be able to swivel so that centrifugal force holds them out. In this way, they chomp at the log until they work through it. Then the shear pin issue disappears. You also need it to run it about 1.5 times faster for greater shear power.

Excellent.

Blades,,,, that's the problem mate,,,, they need to be shaped to pull the wood into the throat of the scissors, not forcing it to the outer end,,,, reposition the "anvil" so it's pointing towards the centre of the shaft, and make concave blades and Robert will be your dad's brother,,,, 💪

I read the title as "Home Made Leg Chomper..." and judging by the looks it wouldn't hesitate to do so....

Cool.yous having good funs

Briggs and Stratton used aluminum key on the flywheel to protect their engines

Thank you very much . Nice . Mar. 17th 2022 Thu. 07:55 am from Yokohama City Japan

Your doin great work out there. That's is a terrifying machine. Guess the next step is a blade guide maybe somthing semi circular

instead of brut force us overwhelming force. Increasing your RPM will increase potential kinetic energy, thus over coming resistance. This will also decrease the blades desire to twist or deflect while under load ... It sure looks awesome thou, in a Mad Max kinda way.... I like it :)

good one tim - great vid mate

Have you considered using an old car wheel rim as your cutter, ive seen this work before, you sharpen the edge of the wheel in a decreasing radius, and you could use a wheel hub with lugnuts for attaching it to the gear box, it woukd be a stronger connection and the curve you cut into the rim can act like a curved knife to cut the logs. Search youtube for an example, there are lots of videos where this method is used, hope that helps. Love your channel and videos, and i hope you have a wonderful day!