HEMTT Material Handling Crane Curiosity

[nf6x]

Hey, everybody. I've been distracted by a home construction project for a quite a long time, and I've been ignoring this board and my trucks. My project and my move are still in progress, but things are winding down to where I can start to think about starting to think about trucks again someday!

So, after various headaches I swore off even looking at the GL web site long ago. Well, this weekend I had a weak moment, I looked at the current GL listings, and danged if something didn't catch my eye!

I've always really liked what Bjorn did with his crane truck, and I've often considered that if I ever had the gumption and money to put a nice knuckleboom onto a 900-series cargo truck, I'd get rid of my tired, old M543A2 wrecker and my last remaining deuce (an M35A2C), and be happy. I never take any of them on the road, anyway, and I just use my wrecker as a yard crane. I'd like it better as a crane if I could control it remotely and the outriggers were power-operated.

Well, it turns out that a big pile of HEMTT rear-halves are coming up for auction real soon, and a bunch of them are not too far from me. So, I'm eyeing those hydraulic cranes mounted on their rear ends, and coming dangerously close to drooling!

Those HEMTT cranes look kinda like the illegitimate offspring of a regular crane and a knuckleboom to me.

So, here I am now, wondering if any of y'all have experience with the HEMTT material handling cranes, and would like to comment on them:

How suitable would one of them be for a behind-the-cab installation on 2.5-ton or 5-ton 6x6, much like Bjorn did? Are they made to straddle a pair of frame rails like a common (?) knuckleboom, or do they bolt onto the HEMTT's butt in a way that wouldn't lend itself to mounting in the middle of a regular 6x6 chassis?

In terms of usability and versatility, how do these cranes compare to either regular hydraulic cranes like the one on my 5-ton wrecker, or a typical knuckleboom?

How do these cranes receive their power? I.e., would there be an electric pump mounted somewhere near them on the trailer, or would they just have a hose pair ran up to a PTO-driven pump on the (missing) tractor end of the truck?

The listings vary between two different NSNs for the trailer assembly. Some of them are listed as having "Wajax boom", and the other are listed as having "Pietzsch boom". I can see visual differences between the two kinds of cranes, and I wonder whether one kind or the other might be better for my hare-brained Frankentruck idea. The pictures of at least one of the Pietzsch ones show a Grove dataplate on the crane. I'd welcome any information or opinions about how these two kinds of crane compare to each other.

It's been so long since I've been active on Steel Soldiers, that I don't recall the consensus regarding posting links to auction listings. I'll just attach some representative pictures of the two kinds of trailer/crane here for discussion purposes.

I'm tempted to go take a good, close look at these cranes. If I did manage to win one, I'd also consider dropping the crane onto my M35A2C's chassis, since a nice 900-series truck ain't cheap!

Thanks in advance for any comments!

 

[gimpyrobb]

Tom (spicergear) put one on his deuce.

 

[wreckerman893]

I would cut the arse end off of a 800 series truck and mate the front of it to that whole rig. What a hoss that would make.

 

[Jones]

Those are actually the back halves of USMC LVSs.
You have two different cranes shown in the pictures. The first crane is a knuckle crane built under Palfinger license and looks bigger than the MHC977 as used on the HEMTTs-- even bigger than the crane used on the M985s. You might want to do some checking on weights before you overload the deuce and end up with a sway-back frame. A 5 ton might handle it better.
The second is a folding (scissor?) crane by Grove like the M985 HEMTTs have.
The HEMTTS (and possibly the LVSs too) use extensions that bolt to the outside of the stock frame rails and the crane and outriggers in turn bolt to them. I'm putting an MHC977 on the back of my baby HEMTT and will be posting pictures in a few days of the extensions I'm making.
PM me and I can give you more detailed info.

 

[nf6x]

I would cut the arse end off of a 800 series truck and mate the front of it to that whole rig. What a hoss that would make.

Well, if I win one of these suckers, I'll make you a sweet deal on the trailer after I pull off the crane!

 

[cranetruck]

Re: RE: HEMTT Material Handling Crane Curiosity

......You might want to do some checking on weights before you overload the deuce and end up with a sway-back frame. A 5 ton might handle it better.
.... .

This has been brought up a couple of times as a drawback for the behind-the-cab mounted K-boom crane....I have not had a problem with this after 13 years of experience with this particular crane use.
99% of the time my boom is extended over the bed for better load distribution.
Having a forward mounted crane is an advantage on a trail, since I can clear it in front as I go, fallen trees or a stuck vehicle in front for example.
A rear mounted crane will also limit the bed capacity when hauling long beams or logs.
A rear mounted crane may effect the capacity of the pintle (tongue weight) .
Any lift is done with the outriggers down, so no load is taken up by the frame.
A 4,000 lb crane mounted behind the rear axle will lighten the load on the front axle and may effect the steering.
Image #2 below shows minimum frame requirements for a 3,200 lb crane mounted behind the cab.
Images 3 and 4 are for the Autocrane A50A series and are close to the performance of my old HIAB...

 

[dma251]

hee hee.....



Here we go again!

 

[cranetruck]

Hmmm...just providing info, the sway-back frame is a weak argument IMHO.
A 4,000 lb crane is not going to have the same effect(s) on a 10-ton truck as it will on a 2-1/2 ton one, so I'm only presenting some facts.

 

[Elwenil]

I wonder what the Grove and Palfinger cranes weigh though. It's hard to tell by eye, but they seem to be a bit heavier than the average knuckle boom. Also, as Gimpy mentioned, Spicergear put a Grove behind the cab of his Deuce. As I recall he had to do a lot of modifications to the outrigger system and the crane base to get it to sit astride the Deuce frame. It also seemed to take up a bit more room on the frame than Bjorn's K-boom. There is a thread here on SS somewhere detailing Spicer's swap and modifications.

 

[cranetruck]

I recall Leonard saying that the Grove crane is almost exactly the same weight as the K-boom on my deuce, 3,800 lb give or take.
That much weight centered about 3 ft behind the rear axle will lighten the front axle load by perhaps as much as 800 lb. I don't know the dimensions of the Baby hemtt, but it may have an adverse effect on the steering.

 

[nf6x]

There is a thread here on SS somewhere detailing Spicer's swap and modifications.

Aha! I've found a couple of threads on the topic:


HEMMT M977 Crane Swap Deuce Project

IT WORKS!!! M977 Crane with PICTURES!!!

I'll study these threads in detail when I get in to work later!

Now, if only I could have afforded Chris's M923A2 to hang a crane on...

 

[Jones]

Actually Bjorn, I'd welcome a little weight offset.
Thought not quite as heavy as the crane/outriggers, the HEMTT cabs are considerably heavier than they look and mine is set forward off the end of the deuce frame by a good foot or better in order to get the HEMTT look without having to modify the frame.
Centerline to centerline; the crane and outriiggers are 31" behind the rear axle while the cab is 51" ahead of the front axle. Difference in weights vs. difference in offsets, I'd say I'm pretty close to balancing out.
Mid-project weights are not relevant but after it's completed I'll take a trip to the scales and see what I have on the front and rear axles as well as finished weight wet.
And, if it helps in the equation, my new wheelbase with the rear axle moved forward to accomodate the crane is 148".
Overall length: face of skidplate to rearmost point of pintle hook 23' 5".

 

[cranetruck]

Considering that you moved the cab so far forward, the placement of the crane may not be so bad, with the number specified and a 4,000 lb crane, the weight taken off the front axle will be 837 lb......

 

[papercu]

Crane

BTY They had a bunch of those trailer/cranes on a G/L sale in Albany GA not too long ago. They sold for anywhere from around 500.00 to 2000.00 ea. I wanted one but couldn't figure out how to carry it home on my pickup.
How/why did the Army/Marines come up about the same type truck but so different? Wayne

 

[Recovry4x4]

RE: Crane

As always, the Marines play to the tune of a different drum.

 

[nf6x]

Re: Crane

BTY They had a bunch of those trailer/cranes on a G/L sale in Albany GA not too long ago. They sold for anywhere from around 500.00 to 2000.00 ea.

Cool. Sounds like a good deal for a crane plus 20,000 pounds of scrap steel!

 

[Jones]

RE: Crane

I've gotten to be a big fan of self-loading cranes-- no need for a loading dock, forklift, ramps, a bunch of friends, an emergency hernia operation...
You just have to figure in frame reenforcement as part of the adaption process. The bare crane weight has to end up as down force somewhere. On everything but glass smooth highways, two tons of anything, flexing up and down is gonna eventually have an effect.
Then with a load at extension, there's torque to figure in; especially if the outriggers aren't directly under the mast.
MV frames are designed for a certain amount of flex over rough terrain but that's using the axles as fulcrum points and allowing it to 'wind-up' one direction or the other. A crane behind the cab shortens the twist area by about half and the wind-up is in two reverse directions at once.
Granted, two tons isn't much compared to some of the loads I've seen deuces and 5 tons carrying; but those load's were distributed correctly, mostly over the rear axles, not piled tight against the headboard.

Kenny, I guess the LVS makes as much sense as owning one tractor and having several different trailers you could tow with it.
But after a ride in one at Barstow can tell you the power units, to drive uncoupled, are spooky at best. Lots of front and rear overhang-- NO (read NO) high speeds, sudden braking, rough terrain, jerky steering movements, jack-rabbit starts.

 

[dma251]

RE: Crane

Leonard - Since you have been in one you can probably answer a question that I've always had about the MK48 power units - How do they steer when uncoupled from their rear unit? Obviously they can have both front steer axles turn in the same direction like any hemtt, but when driven alone, they must have the ability to counter-steer from each other or else the cab's orientation would rotate at all!

I remember a few additional levers in the mk48 cab I got from you. Any idea how it worked?

 

[nf6x]

RE: Crane

Do any of y'all know why LVS trailers are getting surplussed out without power units? Is there a rebuild program where the power units get refurbished and the trailers get replaced with new or different ones?

 

[Jones]

RE: Crane

Damon, if I recall they could either steer with the front axle or "crab-steer" I think the in-cab control says "side slew".
Remember that the front axles don't have the same turning radius as the second steer (front axle turns farther) so they would at least have some semblance of control over direction.

Mark, They may be sending the power units through Oshkosh's RESET program; or they may be afraid of liability in accidents (like the M151s). Then too, Oshkosh may not make the trailers and as such they're being replaced with 'new & improved" ones.