Loader questions and how much is too much?

[Kernopelli]

As I have mentioned, I cobbled my FEL together myself. I found an old Freeman/Bush Hog trip loader at the salvage yard. I cut up the metal from its subframe and used it to make the sub frame and uprights for the loader arms to attach to on my tractor. Cut length/width off the loader arms and build a bucket for it, front support assembly, hydraulics, etc. It works great but I have noticed when picking up a full load of wet mud or sand, for instance, it REALLY flattens the front tires and lightens the rear end. (I calculated that my bucket holds .6 cubic yards). I have begun to wonder: how much is too much without breaking something? I especially worry about over burdening the front axle. I see Koyker recommends their 120 loader for my tractor and it is listed at 1200# capacity. I am curious how to calculate how much force my loader is capable of and worry that it is too much to be safe (damage wise) for my tractor. I have 2" bore cylinders mounted at about 73 degrees with relief set at about 1700psi so the cylinders should have a vertical push of about 10,200 lbs. I know it won't actually lift 10,200# because of the distance between the bucket and the cylinders but how do you calculate for the leverage caused by this distance, (ie: the loader wouldn't lift as much if the loader arms extender 10 feet past the cylinder pivot as it could if it extended only 4 feet? Does that make sense?)? The bucket pin is 44" from the cylinder pin and 76" from the lift arm pivot.

I think a better counterweight would go a long way in taking some of the load off the front end. I have been meaning to build a proper counterweight but haven't yet. I usually use my finish mower as counter weight (about 600# hanging pretty far out back but obviously need more), how many pounds of counter weight would be recommended ? Thanks

 

[kennyd]

I think a better counterweight would go a long way in taking some of the load off the front end. I have been meaning to build a proper counterweight but haven't yet. I usually use my finish mower as counter weight (about 600# hanging pretty far out back but obviously need more), how many pounds of counter weight would be recommended ? Thanks

I think your answer is right there! You NEED to have counterweight when using the FEL. I know my ballast box is about 700lbs or so, and it's still not what JD recommends!
Without knowing more specifics about your tractor, I can't begin to guess how much weigh is adequate.

Another thought: Have you ever tested the relief valve on your loader control? If set to high, with cylinders that are to large you can definitely overload the machine.

 

[RonMar]

Well if my math holds up, .6CU/YD is around 16CU/FT. A CU/FT of dry sand weighs about 100# so your bucket full of sand is a little over 1600# Wet sand is around 120# per CU/FT or around 1900#.

Calculated force at the loader arm pivots would be 10,681# (two 2" cyl at 1700PSI) with a right angle lever arm. To calculate the lift at the bucket, you convert this force applied to torque at the loader arm pivots. Then you convert the available torque from the pivot points out to the bucket to find available force there. With your cylinders at 73 degrees, I am assuming from vertical(cylinders more horizontal than vertical?) then you have reduced your lever arm significantly. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force applied. I estimate your lever arm is about 2' which equals about 21,362 FT/LB of torque available at the pivots. Your 120" of loader arm(is that the straight line distance from arm pivot to bucket pivot?) length makes this easy. That 21,362 FT/lb divided by the 10 foot lever arm results in a 2,136# available force at the bucket pins. If the pin to pin distance is shorter, then the available lift force at the bucket pins will be greater.

At any rate, it sounds like you have exceeded one manufacturers reccomended bucket lift capacity.

 

[RonMar]

I forgot, Got any pictures, preferably from the side?

 

[Kernopelli]

Well if my math holds up, .6CU/YD is around 16CU/FT. A CU/FT of dry sand weighs about 100# so your bucket full of sand is a little over 1600# Wet sand is around 120# per CU/FT or around 1900#.

Calculated force at the loader arm pivots would be 10,681# (two 2" cyl at 1700PSI) with a right angle lever arm. To calculate the lift at the bucket, you convert this force applied to torque at the loader arm pivots. Then you convert the available torque from the pivot points out to the bucket to find available force there. With your cylinders at 73 degrees, I am assuming from vertical(cylinders more horizontal than vertical?) then you have reduced your lever arm significantly. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force applied. I estimate your lever arm is about 2' which equals about 21,362 FT/LB of torque available at the pivots. Your 120" of loader arm(is that the straight line distance from arm pivot to bucket pivot?) length makes this easy. That 21,362 FT/lb divided by the 10 foot lever arm results in a 2,136# available force at the bucket pins. If the pin to pin distance is shorter, then the available lift force at the bucket pins will be greater.

At any rate, it sounds like you have exceeded one manufacturers reccomended bucket lift capacity.

Wow, I'm impressed. Excellent stuff. You also answered a question I hadn't asked yet- the weight of the materials per cubic foot.

Actually the reference to 10 ft (120 inches) was hypothetical, comparing it to 4 feet to explain what I was referring to as leverage. The distance (all straight line measurements) between my pivot pin to bucket pin is actually only 77 inches. The distance from bucket pin to cylinder pin is 44 inches. The distance from cylinder pin to pivot pin is 34 1/2 inches. I got my lift figures (then just rounded off a little) for the cylinders at 73* (from vertical) using this FREE Calculators for sprockets, pulleys, v-belts, cylinders ( hydraulic calculator 2). I am a little confused though (get that way often!). Is my lever arm 77" (from bucket pin to pivot pin) or 34 1/2" (pivot pin to cylinder pin) ? Not sure if "force applied" was in reference to force being lifted at the bucket or force from the cylinders.

Yes, I apparently lifted quite a bit more than I had suspected. I guess I had better start by backing the relief valve off a little. I think a dedicated counterweight is still in order too. Was thinking about starting with 800# of cement cast in a square plywood box/form that allows for some additional cement to be added if necessary. I would like to get enough weight on back to get the front end pretty light without a load in the bucket...similar to how the tractor was before putting the FEL on.

Thanks for the excellent input!

 

[john_bud]

Counterweight should be about the same as the lift capacity. So if you are lifting 1600#, you would want about that weight on the back. That would include filled tire weight.

jb

 

[RonMar]

The distance (all straight line measurements) between my pivot pin to bucket pin is actually only 77 inches. The distance from bucket pin to cylinder pin is 44 inches. The distance from cylinder pin to pivot pin is 34 1/2 inches. I got my lift figures (then just rounded off a little) for the cylinders at 73* (from vertical) using this FREE Calculators for sprockets, pulleys, v-belts, cylinders ( hydraulic calculator 2). I am a little confused though (get that way often!). Is my lever arm 77" (from bucket pin to pivot pin) or 34 1/2" (pivot pin to cylinder pin) ? Not sure if "force applied" was in reference to force being lifted at the bucket or force from the cylinders.

I see, that changes things a bit. lets re-calculate. In doing this calculation, there are two different lever arms. The first lever is for the input 10,681# from the cylinders at 73 degrees and 34.5" from the arm pivot(force applied). At that cylinder angle I calculate the lever arm for force applied to the arm pivot is 10.09" Since we are dealing in FT/LB, it is easier to calculate if it is expressed as feet. 10.09" = .84'. multiply the cylinder force by that number and you have 8972 FT/LB of torque available at the arm pivots. Cool calculator you linked to. Using that calculator, I came up with 8976 FT/LB(3122# of vertical push for two cylinders at a 34.5" or 2.875' lever arm). Once you know the torque available, you could calculate the lift force available at any length arm.

The second lever arm is from the arm pivot to the bucket pivot, 77" or 6.42'. This is the arm that the 8972 FT/LB of torque is applied to. 8972FT/LB divided by 6.42' gives you 1397# of lift force available at the bucket pins.

Are you sure about the calculated size of your bucket? Are you sure about your available hydraulic pressure? Once you subtract the weight of the bucket and the increased lever arm length from loader pivot to the center of the buckets loaded mass, I would estimate your lift capacity at 1700 PSI is under 1000#.

As for material weights, My little black book of knowledge says:
Earth, soft loose mud = 108# per CU/FT
Dry Sand 100# per CU/FT
Wet Sand 120# per CU/FT
Earth, Loam, Dry, Excavated 75# per CU/FT

Any chance of some pictures?

 

[Kernopelli]

Are you sure about the calculated size of your bucket? Are you sure about your available hydraulic pressure? Once you subtract the weight of the bucket and the increased lever arm length from loader pivot to the center of the buckets loaded mass, I would estimate your lift capacity at 1700 PSI is under 1000#.

As for material weights, My little black book of knowledge says:
Earth, soft loose mud = 108# per CU/FT
Dry Sand 100# per CU/FT
Wet Sand 120# per CU/FT
Earth, Loam, Dry, Excavated 75# per CU/FT

Any chance of some pictures?[/QUOTE]

I've been meaning to post some pics but my PC recently died and I had never bothered loading the necessaries on my laptop to download pics from my camera. I'll try to do that tomorrow and share the love.

I absolutly trust your calculations but something isn't adding up.

My bucket is 48" L, 18" H and 32" from top to cutting edge. I used the 48x18x32 and arrived at 27,648 sq in. divided that by 1728 to get 16 cuft and again by 27 and got .592 cu yd. I was a little surprised when I came up with .6 cu yd (I had assumed it was less than that, maybe my instincts are better than my calculation skills). Heck, I'm barely able to find my butt with both hands, it's probably wrong but that's what I used. ...so no....I'm not sure. I honestly don't recall why I used that method to calculate the volume or exactly how I even arrived at it. ( Hard to believe I used to be the CEO of ENRON isn't it!)

The hydraulic pressure is probably correct though, I used a gauge...one of them hydafluidflowometers (kinda rolls off the tongue doesn't it ) In all seriousness though, it is possible I actually opened the relief up a little when I tightened the lock nut down, but it couldn't be much, if so.

One thing I do know is I picked up a bucket (pretty full but not quite) of very wet muddy clay yesterday and was really alarmed at how flat the front went as I lifted it up. The loader had zero problem hoisting it but I swear I could hear 'ol blue screaming for me to dump it QUICK! I didn't even try another scoop. Maybe I'm an alarmist but I have loaded lots of dry dirt lately and it never squats the front like that did. The only other time I was concerned to that degree was when I was moving a pile of sand this spring (before installing the relief..and yes the relief is still working, I seem to bump it quite frequently when curling the bucket).

I absolutely LOVE this forum. All the shared knowledge here is quite an asset to a guy who loves tractors and fabrication but admittedly doesn't know much about them. Thanks again.

 

[RonMar]

My bucket is 48" L, 18" H and 32" from top to cutting edge. I used the 48x18x32 and arrived at 27,648 sq in. divided that by 1728 to get 16 cuft and again by 27 and got .592 cu yd. I was a little surprised when I came up with .6 cu yd (I had assumed it was less than that, maybe my instincts are better than my calculation skills).

"Well thars yer problem right thar"(maybe).

A cube 18 X 32 X 48 is indeed 27,648 CU/IN. But aren't the side walls at an angle from the 18" top, down to the cutting edge? Most buckets are like I have drawn in the attached picture. That would effectively cut your cube volume in half(remove the red portion in the drawing). If this is the case, a level bucket would have a volume of 13,824 CU/IN or 8 CU/FT(black area). Of course any material in the bucket heaped above that sidewall line would add to the load. I doubt you would be able to scoop the whole cube volume with angled sidewalls. This also sounds more in line with the calculated lift capacity.

You used a flow meter to set the pressure? I use a 0-3000 PSI pressure gauge screwed into one of the working ports on the valve, deadheading that port into the gauge. When I send pressure to that port the pressure builds and the relief opens, Relief pressure is then shown on the gauge.

Your tires flattened really bad? Are they pressurized to the specced pressure on the sidewall?

Ultimately what this is comming down to is capacity of your tractor. What would be good to see is the specs on a factory loader, if there was ever a factory loader for it. I know on my Jinma 284, probably similar in size to yours. I also have basically a homemade loader(made by the dealer). I moved a 1300# block of concrete with it a few weeks ago with the blocks setting on the fork bucket. The rear wheels were just about trying to come off the ground, or in other words way too much weight. I moved the same block chained under the lift pins last week and it did it much easier and more stable. I estimate my 5' bucket full of sand might go as high as 1000#. That is a lot of stress on the front axle and is plenty for my tractor. I would rather make a few extra trips then rebuild a handgrenaded axle.

Good luck

 

[Kernopelli]

God, I AM a moron. I've been telling my wife she was wrong for 17 years! Forgot a basic step didn't I....pretty embarrassing in a public forum.

No, I used a 3000psi pressure gauge (just kidding about the hydafluidflowometer thing. I made that name up...guess it was a little too similar to "flow meter" to get a chuckle). Plumbed it into the relief as you had described to set my pressure. I purchased a 3 port relief from Northern Tool and it was pre set at 1500psi and since I had already trashed one hydraulic pump with excessive pressure I was sure to use a gauge when I adjusted the relief valve. Sorry about the confusion. I get the same response when I joke with the convicts at work when I'm bored.....I'm used to it!

I have used the Koyker 120 as a comparison since it is recommended by Koyker for my tractor. Koyker Manufacturing Loader. I would assume it is a practical choice to glean specifications that are considered appropriate for my tractor.

Actually, I do run my front tires a little soft. After putting the loader on I hadn't bumped the pressure up since the loader added a lot of noticeable weight and wanted to maintain a little "cushion" for the spindles and axle when traveling bumpy ground. I had a coworker warn me about the added stresses a loader causes. He snapping a spindle on his JD 4020 a few years ago while crossing a rut (like he had done 1000 times) with a round bale on his loader and it kind of spooked me. Now my tractor could never carry a round bale but a 4020 is huge (4 times the HP and probably 5 times the weight) compared to my tractor and isn't really much of a load for his.

This thread has been quite illuminating for me. Based on your calculations, I don't think I should be too worried as it stands. If the loader would be pressed to lift 1000#, I'm probably in good shape based on my bucket capacity. I do think I'll bump the tire pressure up to 35 psi and add a little more ballast for the rear end and I really think I'll be fine. It is certainly good to now have a close idea as to what my loader will handle and I really appreciate the help.

One last question, what do you use for counterweight and how heavy is it?

Thanks again!

 

[RonMar]

One last question, what do you use for counterweight and how heavy is it?

Thanks again!

I Don't... I am not usually toting around that much weight with the loader, so havn't found the need. I do keep the post hole auger boom on most times for utility work, but doubt it totals 100#

Besides, if I have the front end overloaded, I wan't it to feel squirrly so I can do something about it such as shed some load, or relocate it back farther for better mechanical advantage, as I did with the concrete block.

 

[crbr]

. I get the same response when I joke with the convicts at work when I'm bored.....

Convicts in S. Illinois. I pass your work place often going up I-57 to Bloomington.

 

[alchemysa]

I think a better counterweight would go a long way in taking some of the load off the front end. I have been meaning to build a proper counterweight but haven't yet. I usually use my finish mower as counter weight (about 600# hanging pretty far out back but obviously need more), how many pounds of counter weight would be recommended ? Thanks

I doubt a counterweight will take any substantial weight or stress off a loaded front end. It will add weight and traction to the rear end for sure but that may be all it does. The only way a counterweight could ease stress off the front end would be if it was so heavy or mounted so far back that it caused the tractor to see-saw (teeter-totter) on the back axle. That would make the front end light and could cause more problems than it solved. Adding weight to the rear may 'seem' to help but I wonder how much you have to add to really make any significant difference to the front end stress. Its an interesting question of geometry and physics. I guess it could be roughly tested by loading the FEL then taking a few front end measurements such as front tyre pressure, front axle height etc, before and after the addition of the rear mower.

 

[Kernopelli]

Convicts in S. Illinois. I pass your work place often going up I-57 to Bloomington.

Actually that is Big Muddy Correctional Center in Ina Ill. Used to be up there quite a bit for training but I work further south at Vienna. Coming from Tenn, you probably actually "go by" it too though. It is about 6 miles off RT. 24 at Exit 16. Stop on in sometime, we'll keep the light on for ya

To Ron, wanted to say thanks again. I'm definitely impressed.

 

[alchemysa]

Was thinking about starting with 800# of cement cast in a square plywood box/form that allows for some additional cement to be added if necessary. I would like to get enough weight on back to get the front end pretty light without a load in the bucket...similar to how the tractor was before putting the FEL on.

Thanks for the excellent input!

Youve added, say 600 lbs of metal to the front. (Most of it is WAY out the front!) Theres no way around it... Its never going to be as light as before you added that FEL.

(And all that loader weight is not just WAY out front of the front wheels, Its WAY out front of the BACK wheels! Thats the thing to remember if you are trying to add a rear counterweight to lighten up the front end.)

 

[hbaird]

Thank you for this post and all the responses. I am putting a loader on a tractor that some have said is not suitable for a loader. All this discussion leads me to believe I will have a usable but easily abusable machine. It will be OK for what I need to do IF I go slow and take care. It sounds to me that what you can lift standing still may be too much moving over rough ground. I would suggest finding the Max load pressure recommendation for your tire and trying out for a load or two. My 4.00/16 are rated at 60psi and 320KG each or 1414lb for the front end at 25mph. I expect the 25mph is assumed to running on smooth roads.
Harold

 

[john_bud]

I doubt a counterweight will take any substantial weight or stress off a loaded front end. It will add weight and traction to the rear end for sure but that may be all it does. The only way a counterweight could ease stress off the front end would be if it was so heavy or mounted so far back that it caused the tractor to see-saw (teeter-totter) on the back axle. That would make the front end light and could cause more problems than it solved. Adding weight to the rear may 'seem' to help but I wonder how much you have to add to really make any significant difference to the front end stress. Its an interesting question of geometry and physics. I guess it could be roughly tested by loading the FEL then taking a few front end measurements such as front tyre pressure, front axle height etc, before and after the addition of the rear mower.

Tsk tsk tsk! You must go back to your 10th grade physics teacher and write on the black board "I will not sleep in class" 100 times.

Lets say you put a 1000# cement block (2ftx2ftx2ft) on the 3pt hitch such that the center of the block is 3ft behind the rear axle. Lets further say that the front axle is 6ft from the rear axle. That block is counterbalanced by 500# of the weight bearing down on the front axle. Twice as far x half the weight. So the block is removing 500# of weight from the tires, making them squat less and the steering will be easier too. Added bonus is that the rear wheels will have more traction too.

jb

 

[alchemysa]

Lets say you put a 1000# cement block (2ftx2ftx2ft) on the 3pt hitch such that the center of the block is 3ft behind the rear axle. Lets further say that the front axle is 6ft from the rear axle. That block is counterbalanced by 500# of the weight bearing down on the front axle. Twice as far x half the weight. So the block is removing 500# of weight from the tires, making them squat less and the steering will be easier too. Added bonus is that the rear wheels will have more traction too.

jb

John Bud. I was hoping someone would know the equations 'cause I admit i didnt. . But lets say that 500 lb weight is 3 feet (at the very least!) IN FRONT of the front wheels (as it would be for a loader). In that case youve reduced the lightening effect on the front wheels by yet another 200lbs so the benefit is rapidly disappearing. If I understand this correctly, you're carrying around 1000lbs of extra weight on the rear end, so that you can feel like youve only added 200lb up front instead of 500lb.

Now if we put 1500 lbs of weight 3ft from the rear axle (instead of 1000 lbs) we'll make that (empty) loader feel like it aint there, but 1500 lbs is about half the weight of a small to mid size tractor, so you've doubled the usual stress on the rear bearings in order to remove a weight from the front end that was only 1/3rd more than usual

(Sorry I keep editing this cause I keep finding holes in my argument!)

 

[hbaird]

The math gets more complicated when tire compression is considered. Small amounts of tire distortion will reduce the affect of counterweighting. The rear tires are not a perfect fulcrum. And this all based on a static condition, ie standing still. When moving across rough ground the possibility of resonant frequencies can make more weight on the back much more likely to break the machine in half. I would suggest putting in the maximum pressure rated on the tires, then load the bucket until the tire bottom bulges to your taste. Then go very slow. If it starts bouncing slow way down quick. Very little bouncing is a lot of force trying to break the tractor. Try this at your own risk there is no guarantee expressed or implied.
Harold

 

[john_bud]

John Bud. I was hoping someone would know the equations 'cause I admit i didnt. . But lets say that 500 lb weight is 3 feet (at the very least!) IN FRONT of the front wheels (as it would be for a loader). In that case youve reduced the lightening effect on the front wheels by yet another 200lbs so the benefit is rapidly disappearing. If I understand this correctly, you're carrying around 1000lbs of extra weight on the rear end, so that you can feel like youve only added 200lb up front instead of 500lb.

Now if we put 1500 lbs of weight 3ft from the rear axle (instead of 1000 lbs) we'll make that (empty) loader feel like it aint there, but 1500 lbs is about half the weight of a small to mid size tractor, so you've doubled the usual stress on the rear bearings in order to remove a weight from the front end that was only 1/3rd more than usual

(Sorry I keep editing this cause I keep finding holes in my argument!)

Obviously, you are correct. At some point the load on the front can be so large that the effect of the rear counter weight on the front axle is minimal. That point is usually when you can't back up a hill with a full bucket. When the rear tires are in the air -- well, you're well past that point!

Imagine that you have 2000# in the bucket 5' in front of the front axle. Without any counterweight, the rear tires would lift off the ground (assumed). So the pivot point is the front axle. The rear tires being off the ground, there is no pivot point there. Now put the 1000# counter weight on the 3pt 3' behind the back axle. Imagine for a moment that the rear wheels are still off the ground. You add that weight and it is 1000# and 9' behind the front axle. One one side you have 10,000 ft-lb of torque from the loader's load and on the other you have 9,000 ft-lb from the counterweight + 85-95% of the tractors weight on the other. That is enough to bring the rear down and under control.

While it is only providing 500# of up-force on the front axle, it is still worth having to keep the rear on the ground. One big advantage is that it is reducing the empty bucket load on the front axle. That's a good thing too.

Ideally, the counter weight should be 125% of the loaders capacity. That will as a rule of thumb, remove the empty loader weight off of the front axle. Rigid mounting of the 3pt is often done on older tractors to take the strain off of the hydraulics. While everything will fail with use - I don't worry about tractor bearings and things like that. Breaking in half can happen - rare but it happens-, but usually only when loads are extremely large and shock loading and twist loading present.


Finally, as hbair stated, all this theory is for a static situation and sharp fixed pivots. Reality is neither! It's all very complex, but in general loaders work much better with a generous rear mounted counterweight. About the only real downside is the higher weight reduces fuel economy and will rut the ground.

jb