Ballast Centre of Gravity

[kenlip]

There is an excellent chance that I am over-thinking the problem or that my logic or maths is wrong, but I'll share with you, in the attached document, how I have come to the conclusion that I can't build a ballast block much above 600kg/1,400lbs. People talk about using much higher weights so it would appear there is flaw somewhere in my logic.
View attachment BALLAST COG CALCULATION DIAGRAMS.jpg

 

[Mat4644]

Your tractors rating is 2310 lbs (1047 kg) max 24 inches from the lower lift arm attachment balls. This is where the implement attaches to the tractor on the lift arms. There are more engineering safety considerations built into the factory number other than max lift. If your implement has a combination COG ≤ 24 inches and weight ≤ 2310 lbs it shouldn't be an issue.

My experience you can lift more and a safety factor is built into the factory numbers.

 

[otlski]

Not sure if this was mentioned earlier in the thread, make certain you keep all your check chains and stay-turnbuckles snug so that your counterweight cannot suddenly shift to the downhill side. A heavy weight or implement suddenly moving unfavorably by 8 inches can be what tips you over. Or, at least pucker you up a bit.

 

[kenlip]

Thanks to all who have responded thus far. Lots of useful information, including safety tips from Otlski, which are especially valuable to a tractor novice like me.

Nobody has been able to explain to me the physics involved in the loads at the balls and at 610mm out from the balls. I have decided to consider that to be just an academic exercise for now, and will base my thinking on the 610mm figures. In this case, the +/- 800kg ballast I intend building will be well within spec.

I was talking to someone today who says he has a good source for thick steel plate. If I can obtain some, I think I might change from concrete to steel. Steel has the advantage of being able to make a smaller structure for the same weight. Another advantage could be the ability to addd or remove plates to adjust the weight of the ballast to better suit the task at hand. As per usual, all thoughts and comment about this idea would be appreciated.

 

[Mat4644]

There are probably unknown to us safety, performance and durability considerations the factory design engineers apply to the max factory lift numbers at each location.

 

[jonsstihl]

The versatility of adding and removing steel plates may seem nice until they start rattling around in the box and shifting when you don't want them too. I made mine out of concrete for simplicity but If you have access to plates and they are cheap you just have to come up with a way to keep them from moving. Like pouring them into concrete

 

[PEJ5]

Pour a basic concrete ballast with threaded rods sticking up on top. Then you can bolt steel plates on top as required!

 

[kenlip]

It's getting close to crunch time!

Before I pour the concrete, I’d be very grateful for some help checking the specs of my counterweight.

Tractor is Kubota MX5100 with a Challenge (Australian made) loader

Loader capacity: 1,300kg = 2,870lbs
3-PH capacity: 1,050kg @ 610mm = 2,314lb @ 24”
The centre of gravity of my currently planned block is at 525m = 20.6”

Assuming I keep the COG at the same point, what are….
1. The ideal weight of the block?
2. The minimum weight of the block you would aim for?
3. The maximum weight of the block you would aim for?