Any body built a knuckleboom loader

[muddstopper]

I have been trying to figure out the amount of force I would have at the base of a boom 16ft long. What i think might be correct, but not 100%, sure so I am going to throw it out there as see what others have to say.

I am looking at this as the boom having a lever effect with the root boom cylinder being the fulcrum. With one end of the boom being fixed and the lift cylinder being 2ft from that fixed point, I should have a leverage effect of 8:1(16ft/2ft). Using a 3in bore cylinder at 3000psi should give me a lifting force of 10tons or 20,000lb, /8= 2500lbs of total lift capacity. The total lift weight would have to include the weight of the boom and grapple. This would be with the boom fully extended and at a horizonal position and weight loads would be greater as the dipper boom is pulled closer to the root boom, or as the root boom is raised or lowered from the horizonal position. Does this sound reasonable?? Actual lift capacity would change if the root cylinder was mounted closer or farther than the 2ft number I used as mounting of the root cylinder.

I think this is the way to figure the lift capacity of the boom and cylinders I need to get the lifting force I want. I just dont know how to figure out the actual stress that would be applied to the base of the boom at the swivel. I found that the loader in one of the links already posted, used a shaft of 3in dia, but was only rated for 800lbs with a 9.5ft boom. I found another boom that used a 4in shaft for the swivel, but had a 1200lb capacity with a 11.5ft reach. A 24in diax14ft southern red oak will weigh right at 2500, and I think this would be the heaviest possible load I might encounter. At actual loaded height the dipper boom would probably be at less than half extention so total swivel stress would be calculated at around 12ft of boom lenght. =15000load at swivel base. It seems the closer the load the less the stress at the base, which would coincide with some of the load charts I have found. Well now I am rambleing, Someone tell me if I'm on the right path.

 

[cbailey1956]

Understand exactly what you are trying to accomplish. Went out and looked at my grapple. It has about a 30 inch long hub. Boom and dipper will reach 20 feet. Six inch boom cylinder. Does not like to handle 24" dia by 16' white oak. I don't even try to lift at full extension. Best can do is pull them in about 10' and then lift them up. I have used my new processor one time last week. Built it on a 82 Chevy 350 rolling chassis with one 16' 10" beam on one side to support the log deck. Work in process but it did advance the logs good to cut 16" rounds. If I was going to use a grapple to load logs it would require a lot of beefing up compared to current status. To handle 2500 lb logs I would want stabilizers that reached out at least 5-6 feet from the frame rail to prevent tipping. My prentice G sitting on a double reinforced ford 700 frame rail with its heavy duty stabilizers has led me to drink once or twice with its tipsy feeling at full extension. Back to your boom I think any road tractor drive axle would be sturdy enough using its outer full floating bearing setup. You state boom length of 12 feet. Is this total including dipper?

 

[Roadbuilder6]

Have you considered a Anderson M90
Log loaders | Anderson Group | Agricultural, Biomass and Forestry Equipment

 

[muddstopper]

The M90 only has a lift capacity of 700lbs and a 9.5ft reach. Even the M160 is a little small. Either way, I cant afford one so its a moot point.

I looked at a truck axle today I think will work. A 40000lb axle should give me one spindle and hub capable of holding 20,000lb. I think I can increase that a bit by using a large dia solid shaft connected at the axle flange and supported at the bottom with a bushing. I dont anticipate picking 2500lbs at full boom extention, but should be able to pick it up at half extention. I have to do some more calculating before I start cutting and welding.

 

[muddstopper]

Understand exactly what you are trying to accomplish. Went out and looked at my grapple. It has about a 30 inch long hub. Boom and dipper will reach 20 feet. Six inch boom cylinder. Does not like to handle 24" dia by 16' white oak. I don't even try to lift at full extension. Best can do is pull them in about 10' and then lift them up. I have used my new processor one time last week. Built it on a 82 Chevy 350 rolling chassis with one 16' 10" beam on one side to support the log deck. Work in process but it did advance the logs good to cut 16" rounds. If I was going to use a grapple to load logs it would require a lot of beefing up compared to current status. To handle 2500 lb logs I would want stabilizers that reached out at least 5-6 feet from the frame rail to prevent tipping. My prentice G sitting on a double reinforced ford 700 frame rail with its heavy duty stabilizers has led me to drink once or twice with its tipsy feeling at full extension. Back to your boom I think any road tractor drive axle would be sturdy enough using its outer full floating bearing setup. You state boom length of 12 feet. Is this total including dipper?

Total boom length would be 16ft. With dipper half retracted, lifting forces would be measured at about 12ft. Root boom at 8ft, dipper boom at 8ft, total 16ft reach. 2500lbs at 16ft would be equal to 40,000 lbs at the swivel. With dipper half retracted, 20000lbs at the swivel. I think the only way i would be able to load a 2500lb log would be to drag it as close to the trailer as possible so as to keep the dipper boom as close to verticle as possible. While raising the root boom, should lower the stress on the swivel. I'm just guessing at all this, hoping someone can chime in with a little advice. At any rate, it is going to be hard to find a larger axle to use as my swivel. In reality, I would probably see very few 24inx 14ft redoak logs. Anything that big would most likely be a saw log. And if I do find something I cant lift, the 362 husky will lighten it up.

Since this thing is going to be mounted on the trailer tongue, its important that I keep it as light as possible. It will probably weigh in at 1500lbs, but when traveling, the boom would rest on the back of the trailer to help spread some of the weight. I am shooting for a total combined weight (processor and boom) of around 7000lbs. Thats not counting the trailer. Steel for building will be heavy, but my big weight monsters are hydraulic tank and engine. I am looking at a 190hp 6068 johndeere engine and that thing weights close to a ton by itself. 100gal of hydraulic oil is about 730lbs. add 1500lbs for the loader and I am already halfway to 7000lbs. I recon my f150 will pull it, LOL.

 

[Yooper75]

Muddstopper, we have one of these IMT 16000 Series II 42ft and 6 Prentice Telstik 3300 33ft loaders here at work the manuals for the IMT should give some insight on figuring out what you can lift with your boom. There are some pretty good illustrations in the IMT manuals showing how the turntables are made.

16000

http://www.imt.com/en-US/Component.Display.html?RefId=96b5fb54-4efb-44d1-b2bf-ac4c1c8b8cbf

http://www.imt.com/en-US/Component.Display.html?RefId=779aeaf9-1ee6-41d1-ae8d-726d7312b054

 

[mikefromnh]

Another idea... Instead of a grapple to load the deck, could you use a winch to pull the logs to an oversized log lift? Like what wood mizer has on some of their mills.

 

[muddstopper]

Yooper, I wish I could just find a good used imt crane, but those pictured are consideably larger than what I need. I think to build something similar to the imt with its turntable design would also be pretty costly. I did a little checking on one of those thrust bearings and it was well over $1000. Gearing would also be pretty expensive, altho I havnt actually checked on cost. I kind of gave up on that ideal after finding out what the bearings cost. I will say a double #100 68th sprocket is almost $700, and a double #60 68th sprocket is about half the #100. Going with a axle assembly isnt going to be cheap to build either, but I can source a big axle pretty cheap and it will come with the bearings. I think it would take a lot less machining to make work as well.

Mike, I thought about the winch, but it means dragging the logs thru the dirt and also would be much slower loading the logs. I do intend to add a winch, but it would only be used to drag up logs out of reach of the knuckle boom. I wont be taking this machine to the woods, and will just be pulling up beside a log pile.

 

[Yooper75]

Yooper, I wish I could just find a good used imt crane, but those pictured are consideably larger than what I need. I think to build something similar to the imt with its turntable design would also be pretty costly. I did a little checking on one of those thrust bearings and it was well over $1000. Gearing would also be pretty expensive, altho I havnt actually checked on cost. I kind of gave up on that ideal after finding out what the bearings cost. I will say a double #100 68th sprocket is almost $700, anAd a double #60 68th sprocket is about half the #100. Going with a axle assembly isnt going to be cheap to build either, but I can source a big axle pretty cheap and it will come with the bearings. I think it would take a lot less machining to make work as well.

I know they're not cheap to build much less fix the last boom truck bought was a 2001 with almost 300k on it and I paid just shy of $80,000. It was more for information than anything and I will say that if you find a boom cheap run away as fast as you can because they are pretty ragged out and probably getting to the point of being unsafe to operate.

 

[CDN Farm Boy]

Buddy of mine just showed me a pic of one he saw for sale locally. Old firetuck cab with crane and processor in tow. Hydraulic driven circular saw. $15,000 asking

 

[muddstopper]

Buddy of mine just showed me a pic of one he saw for sale locally. Old firetuck cab with crane and processor in tow. Hydraulic driven circular saw. $15,000 asking

Ottawa aint exactly local to me, but for a circlesaw processor, the price doesnt seem bad.

 

[muddstopper]

Well, I may of scored. Yesterday when heading home from SC, I was running some back roads cutting actross to hit the interstate. I saw a bunch of old bucket truck, and mechanic trucks setting off the side of the road. I made a quick Uturn and headed up the driveway. Young guy was walking out of the shop and I asked him if any of the old stuff was for sale. Of course, everything was for sale. They had a digger crane that had been dismantled and where selling parts. I asked about the base and swivel and yes it is for sale. Owner wasnt there at the time, so I left number. Hope he contacts me today. Parts are super heavy duty for what I want, but can easily be modified if the price is right.

And, I just got shot down, guy wants $1000 for just the swivel. The young guy told me the owner was scrapping and I was expecting a scrap price. Now if i needed the swivel to do what it was designed to do, without any modifications, I could see the $1000 and even consider it cheap.

 

[dcomp]

Wonder if you could use a backhoe style swing. You wouldn't have 360 but they are easier to find as scrap

 

[muddstopper]

My original plans where to use a backhoe attachment off a ditchwitch. I bought a a620 attachment with plans on flipping it upside down to place the knuckle up high. Everthing was there, but it had it drawbacks, mainly weight. The attachment weighed 3000lbs and I just couldnt figure out a way to refab it and put it on a diet. Guy drove up into the yard the day before I started this thread and wanted it worse than I did. I made $500 profit and figure i would just use the money to build from scratch. I am still considering a backhoe swing assembly and think I have one located, but the boom and outriggers are just to heavy.

 

[mikefromnh]

1950s 6x6 Army woods buggy

 

[muddstopper]

1950s 6x6 Army woods buggy

Now that i could work with, but its a long way to Maine. I wonder if thats homemade or a factory build loader. Looks almost homemade, but is certainly not as heavy as some of the factory loaders built for logging.

 

[mikefromnh]

It looks to be a john deere re-branded gafner loader.

 

[muddstopper]

I think I have a plan so I will throw it out to get opinions and ideals.

I think I can use a splindle and hub off a 40,000lb truck axle. That should give me 20,000lb of side load strenght. I will cut the axle tube and spindle assembly from the axle housing to get rid of the big round center section. I will use the tube to weld on supports to hold the spindle upright. After removing the brake drums, brakes, everything but the hub, I will use the wheel flange to build my boom mounts off of. At the bottom of the wheel flange i will mount a large #100 sprocket. Actual size I havent figured out yet, but am considering a 68tooth for gearing. I will most likely use a stator rotor orbit motor with appropriate sprocket for turning. I dont need or want 360* turning, so i will weld some stops to prevent the boom turning all the way around.

. The problem here is the dia of the #100 sprocket which is around 22inches. A #60 68th sprocket is about 16in in dia and has a tinsel strenght of 8500lbs. A #100 roller chain has a tinsel strenght of 24,000lbs, but factor recommendation is to use a factor of 6:1 when determining actual strenght needed. If I use a double #60, I am still less than the strenght of a single 100 at 17,000, but a triple roller would be 25,500lbs. I am considering the triple #60 because of dia of the large sprocket. Sprockets aint cheap, a 68th #100 sprocket is around $750. What has me puzzled is how much force is actually needed to turn a 16ft boom with a 1500lb log suspended from it. I am pretty sure I can hand turn a 16ft boom holding a 1500lb log, so i am guessing it doesnt take that much power to actually spin the boom. I also know from experience that a huge log suspended from a boom can snap a #100 turning chain. I am just guessing, but the boom that snapped the chain had the log help up by a cable and the whiplash of the log swinging probably would put more force on the boom than a log that was held tightly in a grapple. This was on a old Kennemer cable log loader if anyone here has ever been around one. Similar to a BigStick but chain driven instead of cable/cyl turn.

Boom cylinders will be 3in bore at 3000psi. This will give me 10ton of force for lift and keep me within capacity of the spindle. Length of stroke has yet to be determined. For a grapple, I will probably build my own but am considering a Valby rotator, R30 if memory is correct. Last time I checked, I think the rotator was around $700, but I could be wrong on those numbers.

Most of the stuff i have on hand, but buying the sprocket and rotator, and possibly a couple of cylinders, I should be less than $2000 in the boom. Yea, right,, I'll see how that turns out.

 

[muddstopper]

No opinions on this plan???

 

[mikehaugen]

No opinions on this plan???

The only thing I will say, I may have mentioned it before, but the 20,000 rating per side is a straight rating where the load is likely centered between the bearings. What you are suggesting is putting a leverage type load. Not saying it won't be strong enough, but I don't think I would use 20k for the calculation. I liked you idea about putting a lower bushing in as it should help counteract the twisting force to some degree.