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Forklift counter weight taboo calculations

dkmc

Active member
Plenty of sites discuss de-rating forklift capacities for more distant load centers:

http://www.rightline.com/calculator.html#Capacity

What I need is some idea to calculate how much MORE
weight I need to slap on the rear to keep the wheels on the ground....without overdoing it. Then again, the saftey officer would probably lecture that even 10 pounds more is too much. But I suspect machinist types tend to push the envelope a bit if a decent F/L needs a little help now-n-then...

I'm lifting a VMC, about 7600-7700 lbs, only F/L available is a 8000 pneumatic clark. It will get the machine airborne, but the rear wheels do same when I begin to back up with the load. I am figuring the load center to be about 37" instead of the trucks 24" standard. Don't have to go far, about 25 feet total.
Don't want to add more counter weight than is truly needed....

Any estimators willing to come forward?
 

Hdpg

New member
350 lbs of aluminum perched precariously on the back end of the forklift worked for me under similar circumstances. Not that I am suggesting you should do this.
 

jmead

New member
mmm popcorn.
Seriously, does your bull have the hydraulics to lift it level at that load center to begin with?
My experience with Clarks isn't encouraging.
Aside from that I'd think minimum of 500-? lbs depending on how far back it hangs.
 

Stuart Caruk

New member
Last time I watched this stunt, they flipped the VMC off the front of the forks when the chain holding the counterweight slipped and the forklift slammed down hard. They had several thousand pounds of scrap to use for their next jury rig lift though...

My favorite has to be watching to lift trucks with not enough reach pick up a bridge crane to set it on the rails. They picked up the crane from near each end, set it on a huge semi matching set of pallets, and then proceeded to pick up the pallets and move into position. They stopped short and one forklift tipped forward dropping a brand new gantry from about 18' to the ground.

The crane rental, in retrospect would have been a really good deal.

That said, why not try moveable ballast... look for the fattest guys in the shop that have enough brains not to jump off...
 

Milacron

Super Moderator
Kinda tricky to calculate since it's not just the weight but where the weight is located. Rather than stacking more weight on existing counterweight, if you have the manuvering room, way better to hang it as far off the back as possible. I use this standard issue chip bin and fill it with steel plates as needed. I think each plate weighs about 70 lbs. Don't need no stinkin "calculations" ;)

yang2.jpg


yang3.jpg


Both of these machines weighed less than the nameplate capacity of the forklift, but due to all the guarding in the way, the weight center was much further out on the forks than the 24 inch rating, thus necessating the extra counterweight.

maho35.jpg


Of course the chip bin, even empty, is heavy enough you need a second forklift..or shop crane...to lift it into place. If that is an issue, there are ways around that too....many years ago when I operated out of my house, I had an old woodworking horizontal boring machine...probably weighed about 500 lbs... that had a shaft poking out, that I used as counterweight, such that I didn't need a secondary lifting device to attach it to the forklift. The shaft happened to be just the right height where I could back into it and it would catch on the radiator opening of the counterweight and I could then tilt it up to clear the ground with a come-a-long attached to the forklift cage. Looked ridiculous but it worked.

Ah, if only we could just pull a lever in the cab and have the entire rear end extend out... well, for $130,000 we can ! :drool5:

image-versa_lift_25_35_2.jpg
 

dkmc

Active member

Milacron

Super Moderator
I have to be somewhat careful, as the 8000 lb Clark is a neighbors forklift ....not mine....and I'm trying to be covert over the weekend as to this 'added accessory'.
Even the paint is decent, so no "scratchy" on the counter weight, etc.....
LOL...playing Mr. Sneaky, eh ? Sooo, counterweight over furniture blankets may be the order of the day. Put his forks together before you start to make sure that bend you see in one later wasn't already there ;)

bentfork.jpg


The above is what a moron forklift dealer near Greenville, SC had the audasity to send me years ago.
 

Mud

Active member
bentfork.jpg


The above is what a moron forklift dealer near Greenville, SC had the audasity to send me years ago.

Mine were bent like that when I got it. fixed it with a press. 20 years of abuse hasn't rebent it, even with a jib crane attachment so I'm not sure how to make that happen unless you have one severely overloaded with a fork extension on it.
 

Milacron

Super Moderator
Mine were bent like that when I got it. fixed it with a press. 20 years of abuse hasn't rebent it, even with a jib crane attachment so I'm not sure how to make that happen unless you have one severely overloaded with a fork extension on it.
How large was your press ? Mine is 35 tons and wouldn't even think about bending that fork back to normal. At least not within the confines of the press frame anyway.

I ended up fixing it by removing the good fork, turning the bad fork upside down on the forklift carriage, going outside to ground level, then putting my 15,500 lb forklift on the dock.

Then I placed the end of the upsidedown fork under the big forklift and lifted up. It was amazing how much I had to bend the fork beyond straight so that it ended up in the right place. It looked like a bananna during the process, but after numerous lifts* and rechecking the angle with tape measure I finally got it to match the other fork perfectly.


*Didn't want to go "too far"...that's why I did it in "stages"...
 

Mud

Active member
50 ton. 5000 lb forks. The bend was concentrated at the midpoint of the fork, so I just bent it there, between 2 blocks about 18" apart. I actually did it on 2 forks, I bought another set to make forks for my front end loader and one of those was bent too. Maybe yours were made of tougher stuff.
 

Perry Harrington

New member
I have a 1967 Clark 6000lb lift and move a 7500lb VMC with only 400lbs of added ballast. I put a 55 gallon drum on the counterweight, strapped it securely, and filled with water. This method worked very well and got the machine in it's resting place.

attachment.php
 

Ox

Moderator
I'm lifting a VMC, about 7600-7700 lbs, only F/L available is a 8000 pneumatic clark.

Boy - that sounds well beyond doo-able, but if you say that you can almost doo it - then.... :confused:

You can "almost" pic a LOT of weight - as long as one part of the fork is still dragging. If all you need to doo is
Don't have to go far, about 25 feet total.
... then maybe you can doo the skid/slide thing? It's jist a balancing act of picking up as much of the weight as you can while still having some traction on the rears to stear it where you want.

But if your adding - then it sounds like you actually DOO need to lift, and that truck doesn't sound big enough to me.

But then on the other hand (running outta hands here soon) you say that you can almost lift it now. I am really confused? You must be looking to rig this outta the current location - and this is where your issue is? :confused: :crazy:

Well .. enyway ... I have added prolly 2000# or so behind the ROPS on my 8, but only needed a 200# chumm on the back of a 30 to make the diff. :skep: (He said he was "goin' on a diet" after that! :eek: ) ;)


From my experience you should have a min of a 10K for that pic. But if your almost there, keep adding. Fresh tank of fuel. Think heavy thoughts.



Slight tangent here = While I have overloaded my trucks with the best of'm, I Shirley never stopped with the load in the air (more than 4'" enyway) and walked over and snapped a pic of it! :nutter: If the tilt creeps ahead a wee bit [with all that weight on it] it can send it toppling over, and the hydro's are tapped out and could fail at eny time. No need to be eny more wreckless just to take a Polaroid! :rolleyes5:


---------------

Think Snow Eh!
Ox
 

Ox

Moderator
I had the tilt cyls blow a gourd once yrs ago when I was moving a transfer machine base. I had it up and then tilted back and it went "POP" and dumped right back down. Fortunately is was still near ground level! Prolly a 6-8000# base on a 12K turck with 40" load center. ???

WAIT!

That just happened aggin last yr! I had a ??? 9K? VMC on the end of the forks of a MUCH bigger lift (20-30K) as that was all the further the forks would go through and once I got it inside the door it just dumped out. Again - this was NOT a "lose the load" type situation, but if it had been just comming off the truck deck???

And neither of those were overload situations.

I am not Mr. Safety by eny stretch, but come on guys! Use your heads.

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Think Snow Eh!
Ox
 

Milacron

Super Moderator
And neither of those were overload situations.

I am not Mr. Safety by eny stretch, but come on guys! Use your heads.

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I suspect you have some antique forklift and leave it out in the weather ? Only problem like that I've ever had was on an ancient Baker that sat outside all the time. One day I decided to raise the forks all the way with no load just for the heck of it and at the very tip top a hydraulic hose broke, such that as the mast decended every drop of hydraulic fluid that was in the cylinder runs out onto the concrete :angry:

The funny part is that it decended pretty slowly but I had to just stand there and watch it happen as there was absolutely nothing I could do about it...couldn't even find a step ladder to jam under the carriage or anything.

Anyhoo, problems of that nature are highly unlikely on a 2003 forklift that lives inside. Not impossible of course, but life is about probabilities...otherwise we'd never board a jet.

Also, the worse that could happen in my picture senarios is the machine would fall over... never any danger to humans*. And for the machine, I have insurance ;)


*assuming the truck driver in the last picture had normal reaction times anyway ;)
 

Perry Harrington

New member
Ox, either your number's up or it isn't. Whether I jumped off the thing and took a pic or didn't, it was still on the lift and if the lift was to fail, it'd be while moving instead of still. That pic was taken immediately after I backed it off the trailer, I jumped down to walk around and assess the situation and see if I should put the load down right away or continue with the move.

With how the machine is situated now, I'd have the load center a lot closer the next time I move it. I can face the column and get it within 24" of the mast.

Oh yeah, you don't want to lower a load too fast or it'll tip when you stop moving it. That's why it was in the air, didn't want to disturb the CG too much.
 

starbolin

New member
I'm lifting a VMC, about 7600-7700 lbs, only F/L available is a 8000 pneumatic clark. It will get the machine airborne, but the rear wheels do same when I begin to back up with the load. I am figuring the load center to be about 37" instead of the trucks 24" standard. Don't have to go far, about 25 feet total.

That's more than a little overload. Just multiply the weight by the distance. 8000 lb rating times 2 feet is 16000 lb-ft. That's your rating. Your proposed load is 7700 lb times 3 feet, or 23100 lb-ft. To get the error ratio subtract the two and divide by the rating. (23100-16000)/16000 equals 0.44. Multiply by a hundred to get the percentage. 44% over rating. No wonder your tires are coming off the ground.


A saner approach would be to take the forks off and use the mast to lift one side of the machine at a time onto skates. Then roll the machine to it's new home. That way you are lifting half the weight and at zero overhang.
 

Peter from Holland

Active member
mmm popcorn.
Seriously, does your bull have the hydraulics to lift it level at that load center to begin with?
My experience with Clarks isn't encouraging.
Aside from that I'd think minimum of 500-? lbs depending on how far back it hangs.

IMHO
A greater distance of the same load on the forks does not need more pressure on the hydraulics to lift it

Otherwise you could secure a FT just with a bypass on the hydraulics to make it impossible to get it off the ground

If I can lift a load on 1 mtr from the mast I can also lift it on 5 mtr
If I can keep the FT on the ground
A greater distance creates a greater force on the forks the carriage the rollers and the mast Not on the chain or the hydraulics besides a bit more friction

Peter from holland


Peter from Holland
 

Ox

Moderator
No - neither of these trucks were mine. The biggest trucks that I have had are 8's. These were 12 and ??? 25K? Both rentals. Neither one blew a hose. Both failures were internal to the tilt cycls. Or possibly the spools? I know the first time they told me it was something in the cyl tho. Not sure the last time? No external oil either time. Oh - BTW - the 12didn't look very old at all. The 30 was an older unit - yes.

Actually the fork truck rental delivery guy was spotting for me on the way in the building too. All of a sudden the load was going down and he knew that Ox didn't just decide to park it there while he was still motioning ahead. He knew something was up.

Danger of human life/limb? I didn't say enything about that. :rolleyes5: There are plenty of humans to go around. One or two going MIA aint gunna make much diff. If someone is there watching this all go down and decides i'd be a swell time to check out the bottom side of the load, then maybe they desserve what's commin' to them?

I'm talkin' IRON! :D


Perry, once you got off - you jist lessened your trucks load cap as you jist removed some of the ballast. In the time you got off and wondered over there to take the pic - you could have jist backed up another 2' and been sure of your situation and lowered it. Besides - with an 8' gap between your machine and the trailer - I'm guessing that you should have had a pretty strong sence that you were clear. :Yawn: (I know that your much smarter than that. :D )


Per Peter - You know - that would make sence, but jist doesn't quite seem to be the case.


And BTW - NO - my fork trucks sleep INSIDE! Although I did have a block heater added to my 8 jist in case it hasta sleep down to the other building in the winter sometime.


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Think Snow Eh!
Ox
 








 
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