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Twin Steer or Reverse Steer Tag or Ideas?

Discussion in 'Trucks' started by lumberjack, Mar 12, 2017.

  1. crane operator

    crane operator Senior Member

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    The air up, air down, and lock pin are all controlled by electric/air switches you can see at the rear, and a air regulator set for pressure on the lift bag. I just used a smaller trailer plug connection for my controls, and its own wire, and a regular trailer plug for the lights, then the regular air lines, like it was a trailer (makes it easy to unhook).

    I used a steer axle on this crane, because with the large outrigger boxes on it, it sets a long way behind the drives.




    20170318_104738.jpg



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  2. crane operator

    crane operator Senior Member

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    If you start adding axles and/or moving stuff around, do you have to go through a whole re engineering of the mounting system? It's a manbasket capable rig- they usually have to engineer where the weight is exactly and what it weighs, so just moving the axles forward would be possible, but it changes your counterweight position. Would you have to pay for that to be done? I would see what costs are involved with that also.

    I'd be a little concerned that the engineering report is so far off from what the rig actually weighs. I wonder if they used this actual mounting (your rig), or if they just gave you the manufacturer's minimum recommendations for the crane (or some similar mounting they did in the past).
    This is what national gives you when mounting (page 3 of the pdf)- they say at the bottom to perform a actual test as mounted- and I'm sure there's a test procedure. If I was in the manbasket, I'd want to know for sure.

    With your front way heavier than the specs, all that weight is beyond the front outrigger boxes, making it act like a load when the boom is out over the front, it makes great counterweight when your out over the rear, but that's all supposed to be in the drawings, and in a new rig I would want it to be right.



    I should have the pictures of the non steer tag later this week.
     

    Attached Files:

  3. lumberjack

    lumberjack Senior Member

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    I did make an error in my calculations, used the front axle for my measurements but the front bumper for my calculations... I guess having a 2 month old will do that!

    I assume taking the axle off and on is not exactly a good time getting the pins in and out?

    Moving the drives forward would move the CoG forward as well. That would mean the weight on the front could be reduced, if I was so inclined. The two main concerns I have over moving the axles forward are stability reaching over the side (torsional rigidity of the subfram) and point loading on the frame. I don't believe either will be a major concern. Tipping over the front of of fairly low concern with a rear mount, over the rear is the bigger concern.

    The stability test for the truck is fairly simple, pick up a weight, push it all the way out, and rotate it 360* making note of how high the opposing tires/outriggers lift off the ground.

    As opposed to a stick boom, knuckle booms are quite flexible both in terms of usability and setup, including the outriggers. The outriggers can be set up anywhere in their span, vs short, mid, or full span. Also, the tires of the truck stay on the ground, even if you're not level. Being particularly level isn't required. You do want to do most of your long reaching inline with the slope.

    IMG_4090.JPG IMG_4092.JPG IMG_4117.JPG
     
  4. crane operator

    crane operator Senior Member

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    It's not as bad as you think it would be- with the three jacks on it you can tip it every which way, but I only drop it on pavement. I wouldn't try to drop it on a uneven ditch. It helps to have someone with you to hook back up.
     
  5. td25c

    td25c Senior Member

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    Last edited: Mar 19, 2017 at 9:49 PM
  6. lumberjack

    lumberjack Senior Member

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    Thanks! Sitting at her 2 month checkup now.

    It does have a 100% 360* chart. The specs for lift on the passenger side outriggers (lifting over the driver's side) is 12" on the rear and 6" on the front! So far I haven't seen more than a quarter of that. I plan on doing some testing to see how much safety factor the truck has for stability.

    That testing will also let me calculate the reduction in capacity with the truck being out of level. Keeping the truck inline with the slope should keep the reductions to capacity very minimal. At some point the more likely issue is the truck staying on the slope traction wise between the rears and the ground. Chocking the tires and/or using a winch is an option for that. Stability wise you can also add weight to the deck.

    A 10* slope only moves the center of gravity 1.5% back... negligible. That's a bit over simplified, but yeah.
     
  7. crane operator

    crane operator Senior Member

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    So just so I'm clear- the chart/capacity on the label on the rig is 100% of capacity? Cranes on outrigger's charts are 85% capactity, on rubber is 75% and manbasket work require's 50% of chart. I would think that they have some derate measure for if you're up in the manbasket? Does the rig have a pressure shut off on the boom cylinder that's set for capacity (a lot of small boom trucks are that way- so much pressure on the main boom cylinder and it will just bypass)? or are you all on your own and it will pick until it tips? (I'm just curious how its set up, I like to learn :rolleyes:)

    Then again, we're probably overthinking this whole thing, just add a axle in front of the tandems and one behind, do a few test picks to make sure you haven't affected stability of the crane, and go make $. I would probably just add one close to the tandems to save moving as few tanks as possible, and keep checking your weights, then add the one behind last. I can see where getting the axle loads down would really help in residential yards, and crossing sidewalks. Moving the axles ahead would lighten you up front, but won't reduce the overall ground pressure like some extra axles would.

    I could see that being a great rig for taking down dead trees, no danger of being up in the tree and trying to rig it up and fall it, and much less need for extra men also.

    Also- I rarely unhook the tag axle on either crane. 50% I never touch it. 48% I pull the bottom pin so the axle will float (off road and steep terrain). The other 2% I unhook it, for either getting really close to something, or if I'm going to need at the big tow lugs on the rear of the crane carrier to hook up to a excavator to pull me in or out of a jobsite.
     
  8. td25c

    td25c Senior Member

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    Oh Man ! I know how that go's . I heard they eventually turn into teenagers ? Hang tough lumberjack :D
     
  9. td25c

    td25c Senior Member

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    That's cool , sounds like you can grab a load and good for the full 360 degree swing .
     
  10. crane operator

    crane operator Senior Member

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    My oldest is a senior in high school, off to college next year - and I have no idea where the time went. If I mention that we are probably closer to grandkids, than when we had our own kids, my wife gives me odd looks. I don't feel any different than when I was 20, but my hair isn't quite the same color as it used to be either:rolleyes:.

    Congrats on the new girl, enjoy it, it goes fast.
     
  11. td25c

    td25c Senior Member

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    Are we still talking about the knuckle boom rig or a old school 750 Holmes wrecker ? :):D
     
  12. td25c

    td25c Senior Member

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    Boy aint that the truth Crane Op !

    I'm in the same boat . At little league ball games I look at the parents & some of them look like they just got out of high school .
    I get mistaken all the time for my boy's " Papaw " . LOL ! :D
    Dealing with equipment ,trucks & cranes is allot easier than raising kids :)
     
  13. Junkyard

    Junkyard Senior Member

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    The more I've read this and thought about it I could see where a couple axles would be beneficial. Any more news on the reverse steerable axle? I may have missed that. We've been so busy I can't goof off, oops I mean stay caught up on here :).

    Congrats on the kiddo. My oldest turns 18 Thursday. She has her moments! Youngest is 2-1/2. Three between them. Pray for me! Lol.

    TD before I had a hydraulic crane on a truck I had a Brockway with a 750 Holmes, extendable booms. Had a drag winch with about a half mile of cable on it. Came from Maine I think it was. When they took a field trip and needed winched out they must have really gone into the bush!! It was easy to run out the back, lift until the steer tire was off the ground, then go a little more! Off the side I'd sometimes swing the leg out, set it a foot or so off the ground and quit when it touched. Kind of like an indicator. I can't believe that rusty old frame never split on me. It was even the super deluxe body :)

    Off topic I know!

    Oh btw, iron is waaaay easier!

    Junkyard
     
  14. lumberjack

    lumberjack Senior Member

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    The chart has weights at various points, but the crane doesn't have a LMI. It has pressure transducers on the various boom cylinders (but not the extension cylinders) and the readout on the remote is in percentages. The computer stops you when you hit 100%, however there's a high pressure, low speed setting that gives you a 10% boost by slowing the boom down. This chart doesn't show the single manual pull out that adds 6'.

    2017-03-07 10.20.37.jpg

    We have a 15 year old and a soon to be 12 year old also! The baby was supposed to be born on 3/13, the boy was born on 3/12, and the girl 3/29... the baby (Carly) decided to come on 1/19 which worked out greatly for the best.

    Yes sir, on some setups the crane has derated portions of its rotation and it tracks the z axis/rotation of the crane to adjust the percentages when in those areas. My crane is 100% for 360, so it doesn't keep track of the rotational position.


    Thanks! I could be a grandfather in another 10 years I suppose, that would put the oldest at 25.



    The reverse steerable axle works like I thought and is rated for 13200lbs and a single 22.5 or 24.5 tire/wheel. The crane dealer is waiting for me to give them the part number to order the axle.

    I am meeting with my mechanic in the morning to see about moving the drive axles up. I can move them up to 61" forward by moving the step ladder holder and the tool box.

    It still crosses my mind to move the drives forward and add a tag and pusher to the truck... we'll see, my money reserves are fairly depleted at the moment!

    Here's some pictures playing around this afternoon, showing the truck to my aunt. Good for roughly 800lbs with the manual pulled out... 1300lbs if I give up that 6'.
    2017-03-20 18.43.48 HDR.jpg
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    2017-03-20 19.12.50.jpg
    2017-03-20 19.12.50.jpg
     
  15. td25c

    td25c Senior Member

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    That will be interesting to hear what the mechanic has to say about it ?

    Just looking around Truck Paper found a few trucks with rear mount knuckle cranes similar to yours for ideas ? http://www.truckpaper.com/listings/trucks/for-sale/18462975/2017-freightliner-114sd
    http://www.truckpaper.com/listings/trucks/for-sale/4818461/2005-mack-dmm6856s
    http://www.truckpaper.com/listings/trucks/for-sale/17279585/2017-western-star-4700sb
     
  16. Steve Frazier

    Steve Frazier Founder

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    Is that a common way of doing tree work in your area? I've never seen this method before! Here they use either a bucket truck or climb, occasionally a traditional crane to hoist a large tree from a spot with limited access. It sure is an interesting idea.
     
  17. lumberjack

    lumberjack Senior Member

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    I was talking to him about pricing/feasability of moving the axles, adding the tag or pusher (or both), and plumbing for trailer brakes. Shooting from the hip, it's looking like a 2 week job, probably $10k plus the lift axle. 2 weeks meaning 80 hours at $85/hr... I didn't get a price on doing the steps separately. Moving the axles doesn't seem like that big of a job, but maybe it is.


    Thanks for pulling up those trucks. It's funny, all 3 have the drives forward and a tag axle at the back.
     
  18. lumberjack

    lumberjack Senior Member

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    No, there are less than 40 trucks in the US doing tree work this way... it's a very new idea in North America, more common in Europe.
     
  19. lumberjack

    lumberjack Senior Member

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    I shot a video of this job, didn't take a before picture, but here's the last piece of the tree being removed from somewhat of a tight spot!
    2017-03-21 16.24.08.jpg 2017-03-21 16.30.57 HDR.jpg 2017-03-21 16.32.20-1.jpg 2017-03-21 17.10.11.jpg
     
  20. RZucker

    RZucker Senior Member

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    Moving a set of drives is a job... Look up in between the axles, there is normally a huge crossmember midway between the axles that may have a gazillion bolts or huck rivets to remove and redrill holes to move it with the axles.