Add a Crane: A Handy Helping Hand for Your 1/4 ton Military Trailer (1 Viewer)

[greentruck]

When it came to hauling stuff, the 1/4 military trailer had it all -- except a tailgate. This made for a stronger tub and the easy reach-in distance still makes these trailers popular with off-roaders. As we age, though, that reach-in begins to present obstacles. And if there's something heavy, it can be tricky to unload for a variety of reasons if not hitched to a tow vehicle.

Then there's fools like me, with a bad back, but who hauls all the comforts of home to the woods though I know better. Throw into hitting the big 6-0 and reaching into our beloved M101 CDN began looking like a painful chore. What to do?

Several others outfits offer similar cranes (Northern Tool, for instance.) Good ol' HF offers several solutions, with the one I chose being least expensive. It was HF #60732: 1/2 Ton Capacity Pickup Truck Crane
HF also offers the #60731. It's a virtually identical crane mounted on a tall pedestal, with a winch and cable to use as a hook. I liked that, but decided 60732 worked better for our needs. Why?

As my wife pointed out, a crane that took up floor space in the trailer was a negative. I was intrigued but cautious about a mount on the trailer tub, probably on the front bulkhead. I didn't want to permanently alter the trailer any more than I had to -- and I didn't want to create a weak or dangerous situation. I'd already added a tray to hold our LPG tank and its attaching frame meant most of the holes I needed were old news.

I'll return to describe it more carefully, but how about a dramatic reveal to start things off. When done, the old tarp fit petty well...

View attachment 1271178

 

[greentruck]

Underneath the tarp was my new strong helping hand, the HF crane.

more in the morning...

 

[e9999]

keep the tarp on or all your neighbors will come with request to help them go get the big rocks they want for their landscaping ... although that could be fun!




OK, I'll admit I have contemplated coupling my engine crane and trailer somehow...

 

[greentruck]

OK, now for some details. Here's a view of the bottle tray. I bolted posts of 1.5 square perforated tubing inside each back corner. the lower 4 bolts through the front bulkhead were already present, but I upgrade the bolts to 7/16".

The 2 upper bolts in the middle and one at each end pierce the bulkhead right below the square tube tub lip. They are all 3/8".

Here's a side view of the framing around the gas cylinder tray.

Next is a top side view, where you can see the crossmember of 1.5" square tube behind the top lip of the front bulkhead.

The perforations provide tie down points. You can also see the oak rubrail.

To provide a wide margin of error for my hillbilly engineering, I limited the crane to 500 lbs, more than I'll likely need.

 

[greentruck]

E9999,
Our rocks around here are mostly imported, due to the glaciers scraping things clear some time back. If I worked on a mileage rate, that could be lucrative...

On the M101CDN, tying down your boom is easy because of the handy flip out internal tiedown rings.

Since these rigs get used offroad, I took the liberty of inserting washers as spacers to take some of the slack and slop out of the HF crane. The pivot point.mount for the boom here with the pin through it is one place that's a good idea to do that, in addition to using the tiedown points. A 1/2" washer neatly takes up the extra slack on each side of the boom tube in between the mounting brackets.

The ring I installed at the top of the crane post is a forged one with a 2200 lb safe working limit, again plenty of safety margin for what I plan to do.

Here's the factory config for the lift chain and hook.

 

[greentruck]

Then I had to improve things...

Keep in mind that much of the hardware, etc, you see here has warnings all over it about not being rated to lift. OK, but like the 2200 lb SWL ring, it's unlikely to fail in use. The thing is that lawyers are understandably nervous about lifting stuff, as so much can go wrong. Provide yourself with plenty of margin and use safe operating practices and you should be fine. I am not an attorney so don't take this as legal advice. It's what works for me. YMMV.

Here's what the ring is for, attaching a 1 ton come along. I still need to get a clamp to put around the opposite end of the come along to keep it from falling off with slack in the line.

Here's what I did to give the crane more versatility.

The end of the boom as modified with a top slot and the original lower slot is opened up to get the come along hook through it.

I used a 2" pulley from small block I bought at the hardware store on a axle made with a grade 8 5/16" bolt. If anything, it's the weak link in this system, but if I have problem with it, it's likely due to an overload. It fails safe, because the rope is retained in the boom.

 

[greentruck]

Time for some testing. Probably the biggest load I'm likely to move if my shop compressor. It's also bulky, has a weird center of gravity and tops out at greater than what I could deal with on my own. I also picked up a HF load leveler for just such situations, as it makes it easy to deal with such difficult characters. And here it is, hoisted in the air a little over a foot -- when the garage ceiling got in the way.

The lean in the trailer is mostly about the tire on that side being low. The compressor weighs right at 200 lbs. If you do run into a heavy load, getting in the trailer (at least for me) adds 250+ lbs as a counter balance. The hydraulic ram swivels to allow you to pump it from either side.

Also note that I've got the load BEHIND the front bulkhead, so you do have to be careful it doesn't swing around in front of there or it could be trouble in cases like this.

Oh, and don't forget to set your parking brake or otherwise block the wheels when lifting. Don't follw my poor example here and forget to set the brake.

Some more on sizing up potential loads coming next. Gotta take care of some business right now.

 

[Chris Wilcox]

This is really neat. I may use it as inspiration for another project.

 

[e9999]

would the crane lift the compressor high enough vertically that you could put it in the trailer?

 

[greentruck]

e9999,
The answer is yes, it would. In fact, that's where the next set of pics goes. This question is one that every user should consider in designing their mount, although the question really applies to the prospective user's needs [>insert favorite heavy item to be moved here<].

Some numbers first. The crane stands about 16" tall, but keep in mind that the boom doesn't go below horizontal. It's mounted on the lip of the trailer, which is 44" above the ground. Importantly, the crane lifts to max of ~60" above its base. Keep in mind there's some rigging always, even if just the hook, that means you actually have less overall lift to work with. This pic shows crane boom at full up.

The air compressor is just less than 48" tall. The way I rigged it in the pics above is probably not tight enough to clear the side of the trailer, but I knew I couldn't do it in the garage, so didn't bother. This pic shows the boom at 56" when the hook is 8" away from the side of the trailer.

Also remember that as the crane goes up, the point where the hook falls vertically gets closer to the crane base as the boom rises. So you also sometimes have to take the size of the lifted object into account, as it can't get too close before it's high enough to clear.

Another point is that the hook is roughly no closer to the ground than about 60" (44" to trailer top of bed + 16" height of crane when it is lowered to full horizontal) so you may need a sling to reach it if you have only the fixed hook. You may still need a sling with a come along if the lifted object is short, but depending on how much cable is on the drum if might be possible to directly reach an object on the ground and hook on. But this need is why I went ahead with installing the come along, with the idea that it's used to reach down to the load, lifting it to the max possible, then using the crane's hydraulics to do the rest.

Finally, at max boom extension, you have roughly 32" of reach past the edge of trailer tub.

Sure wish my dad and I had this rig the last time we got a road-kill deer. had to hang the thing from the rafters in the garage and that wasn't easy for two old guys who shouldn't be lifting much, let alone a big ol' buck. So besides rocks, I'd expect this sort of mod to be very popular with the hunting crowd. And if you like your solar shower to build up a little pressure, this is an easy way to get it up higher.

 

[e9999]

That's nice. The extension helps a lot with that. Gives you quite a bit of extra reach.

 

[greentruck]

That's nice. The extension helps a lot with that. Gives you quite a bit of extra reach.

Yes, at full extension is where the 500 lb rating comes from. The alternate, shorter boom lengths are rated at 600 lbs, 700 lbs and 1,000 lbs respectively. But you only have 33" of reach at 1/2 ton, which puts you at about the same spot 8" outside the trailer tub lip as in my pic of it at 56" earlier. You could lift something heavy and compact. And if you used the factory rigging configuration of the short chain and hook, the 1/2 ton doesn't seem unreasonable.

But with the come along and my mod to use it, I dunno. The come along is rated at 1 ton, but the weak link there is the sheave at the top of the boom. I extracted it from a small metal block that was rated at 480 lbs. I suspect that is when the two halves of the block holding the sheave would fail, as they were stamped and riveted metal. The sheave itself was cast, AL I think, with a bronze bushing to rotate on. The axle is a Grade 8 bolt, but only 5/16" diameter. This could be upgraded if you did need to lift heavy stuff frequently.

But the big factor is how heavy the trailer is. As I noted with the air compressor, it was heavy enough to offset the compressor weight of 200 lbs. A F block at ~600 lbs would likely need outriggers, at a minimum.

Reach is good though, particularly for bulky, light objects, like my trike sitting in front of the trailer in some of the pics. I never considered trying to put it in the trailer myself, but with the crane, it would be trivially easy. I also have a snowblower, so the crane also makes it easy to trundle it around, because an 80 series wasn't made for that sort of pickup-trucky stuff and a flatbed trailer isn't near as handy as a M101 CDN.

 

[cruiserpilot]

To me, the center of gravity of that thing is way up in the air. The base of the crane should be right at the floor
of the trailer. Especially if you start reaching out. I don't know the physics, but go talk to a proper crane operator
and get a second opinion. I have a bad feeling about that set up. The whole mounting set up kind of makes me
nervous. Maybe I'm way off base, maybe not. I guess it depends on the weights you are
thinking of lifting.

 

[greentruck]

I've been urging a cautious approach to this as I go. Obviously, things could get off-center enough to flip the trailer on its side if you worked at it. But let's think of it this way. For objects to get in the trailer, you'll have to use the crane (unless you're using someone's else's gear to load it.)

At the point of loading, you have to pick the object of interest up. At that point, the boom will extend out farthest in terms of reach. In the normal course of action, i.e. using the hydraulic ram to do the lifting, the moment of truth is when you start lifting. It's also when the load has the least distance to go before getting back on the ground. As you lift, it gets closer to the COG, which tends to make it safer as it goes up (while still requiring attention as I'll note below.)

When I lifted the air compressor today, you could tell the trailer got a little light on the opposite side. As I noted, I should have pumped up the curbside tire with the compressor before I tried lifting it, as that tire's rim is so corroded it leaks off, which exaggerated the squat to the load side in the pic. Still, the compressor lifted off without lifting the opposite of the trailer. Once I crawled into the tub on the side of the crane away from the load, things settled down more. I'm heavier than that compressor, so my weight compensated for the load's effect on the other side.

Same thing if you have a loaded trailer and take the first, heaviest item out first, the rest of the load helps keep the COG low. When we're camping, that will be the chuck box. It's heavy and a little awkward, but lots less of both than the compressor was.

Assuming you're on level ground, parking brake engaged, and no sudden gusts of wind, anything you manage to safely get into the bed with the crane should come out equally safely. I've already noted the caveat of keeping the load behind the crane's bulkhead mount.

The complicating factor is the come along. If you use it to raise the load, instead of the hydraulic ram, then the boom does not get closer to the COG as the load goes up, so you might run into trouble that way. The cable is used in order to reach the load, then the ram does the lifting and gets the load close to the COG to be safer.

Working from that, you have to know what your load is to be safe, just as a crane operator would. And you have to know your equipment's safe parameters of use. They're posted right on the crane. And they are exactly the same as on the 60731 crane. Its pedestal, BTW, would place the whole thing higher up than the mount I made on the tub edge, which seems problematic to me.

 

[greentruck]

I did some more thinking about cruiserpilot's concerns, double-checking my rough calculations on this.

I discovered I'd badly garbled what I was trying to describe about how I derated the 1/2 ton crane. Basically I was lazy in painting out the factory labeled boom locations and leaving just the 500 LB one at the farthest extension of the crane. In my mind, that's the max capacity of the crane. But that label is right where it always was, next to the farthest location of the boom. That's clearly wrong if I've derated the capacity of the crane as as a whole to just 500 pounds, as that should be at the position all the way in rather than the outside end position. So I did some more painting and got out the label machine.

I think the 200, 300, 400, and 500 lb numbers are pretty conservative, although yet to be fully tested obviously. Also, a reminder that the comealong is supposed to be used for taking in slack, not lifting.

Next, more good advice, basically don't get between the crane and the load.

Some basic set-up info for safe operation.

Tying down your boom and avoiding needless pivot is a good idea.

 

[greentruck]

More...I also updated the capacity vs boom length numbers on the crane label.

I needed a place to stash the ram handle and found these clips for hanging up your broom. They fit supertight, then I cinched them with a tyrap just to prevent an easy time for parking lot prying fingers.

I also need to find 4 plastic endcaps for the 1.5" sq perforated tubing I'm using to support the crane mount. Mc-Master Carr I suppose? Anyone know of a source?

 

[e9999]

Nice.
Crane looks just the part on the mil trailer.
And I can tell you do love your label machine!

 

[greentruck]

Thanks, e9999. Just wish I had a label cartridge for my fancy one right now, they're more weatherproof.

 

[scrapdaddy]

OK, now you're just showing off with the label maker. Really though, good job on putting it all together. Someday I want a lift crane on my deuce.

 

[greentruck]

SNIP
Someday I want a lift crane on my deuce.

You'll want to consider rigging a comealong with more cable than my 1 ton for that. The 2 ton they had would probably work. I'm just thinking it's farther to the ground from the bed of a deuce.

Or save your quarters and buy a HEMTT. Many come with a crane included in order to deal with those huge spare tires. Then there's these handy ones...

Pic via Military Information HQ