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I got a KNUCKLE BOOM !! Need mesurments

rchalmers3

Half a mile from the Broad River
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Irmo, South Carolina
I have a few general questions for you guys who have fitted knuckle booms:

What is the least cost method for adding hydraulics to a winch truck: fitting a 24v electric power head or sourcing a transmission PTO, pump and tank?

For bracing the frame, what about a fabricating a spider "spreader" sub-frame for the boom like those found on trucks like the Unimog. This spreader disperses the boom load from behind the cab back over the rear axles, on top of the chassis without doubling the frame. I ask about this because in my location there are limits to the availability of "C" channel sources.

Will standard 4"x4"x 1/4" tube work or do I need low carbon or another special material to build the subframe?

Thanks all,

Rick
 
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spicergear

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Why double the frame?!? The base under the knuckle boom is what spreads the load out. Standard frame is sufficient...outriggers take the loaded load off the frame (you know what I mean) and the frame base spreads it out on the frame.

The 'mog spider frame is a good idea but overkill on a deuce. The deuce has 5,000 - 6,000 lbs on a 406 truck and a lot more wheel base to stabilize the truck so it doesn't need the four corners of the bed like the Mog set up you're referring to. Plus those are usually pretty expensive.
 

Speedwoble

Well-known member
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New Holland, PA
Not real glamorous but heres a few after stripping the frame and droping the new rail on. First pic is of the rails before they where cut.

Oh yea, Fwiw. I have less than 5min into removing all my rivets :grin:
So... inquiring minds want to know what the donor for your doubling frame was. I was planning on bolting directly to my frame, but am considering doubling it now.



What is the least cost method for adding hydraulics to a winch truck: fitting a 24v electric power head or sourcing a transmission PTO, pump and tank?
Option C, buy a knuckleboom with an auxillary engine already installed. :D
 

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ODdave

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I went with doubling the frame because I wanted it to be as low as posible and I figured by the time I fishplate the frame plus add the tube on the top it would be just as easy to go this route.

The frame rails where new ones from the scrap yard. I assume they came from the local heavy truck / military vehical bulder. They are 9in tall so I assume there for a school bus.
 

Jeepjake

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Bend, OR
"Too big.." I don't understand :mrgreen:

I am certain that it is not too small!

My assessment would be this: Physically it will fit, and be below max height (right...!) which is 13'6" here in the PNW, not sure if local municipalities have tighter regs due to local road infrastructure, but i digress.

the crane may very well be capable of lifting an object heavy enough to cause structural damage to your frame if not properly reinforced, so simple. determine what that load may be, and limit the hydraulics to make it incapable of hurting the truck.

the only penalty you will end up paying is the added weight of the crane that is "overkill"

Cranetruck may be a good resourse in determining what coupling moment his crane is capable of delivering to the chassis (greatest weight * distance) this may be a good starting point.

Myself I only have an 8000 lb crane, so I am not too worried about overstressing the frame.

-Jeep
 

Jeepjake

Member
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Bend, OR
Here is where the moment comes in, Something tells me that crane will be able to lift 8K at a distance far greater than mine.!!

Mine is a HIAB 173 speedloader and doesn't have near the reach as yours.

My load rating is at roughly 8 feet from centerline at the most inboard attachemnt, and the load rating reduces rapidly from there.

My maximum reach is 15 feet

-Jeep
 

spicergear

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Maybe you want to reread my earlier post now?

Center the crane side to side on the truck, figure where it has to be to rotate and not hit the cab and sock it down. Yes, any large attachment is capable of damage to the truck frame but you have to use common sense.
 

ODdave

New member
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lansing michigan
Maybe you want to reread my earlier post now?

Center the crane side to side on the truck, figure where it has to be to rotate and not hit the cab and sock it down. Yes, any large attachment is capable of damage to the truck frame but you have to use common sense.
Why would I need to re-read your post? The hoist is not in its final resting spot, I only get about 2 hours a day to work on it so the rails are not fininshed. I set it on the truck because the snow was gone for a day and I had to take advantage of that. Keep in mind, I am doing this by myself so things move slow.

I get your point about the 3x3 tube, But is there something else I am missing? The added rails are stronger than tube........
 
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