3 point lift issues

[SPYDERLK]

Yes. The 3ph is essentially an imperfect [parallelogram] four bar linkage. When perfect this lifts a weight without pivoting it. Distance of the weight outward from the lifting force is immaterial except its effect on backtip.

Does what you said, make sense to you if you think about it? The load set far back can “effect backtip”, but has no effect on the force to lift it up?

Yes. That backtip resultant (a torque) is transmitted by Tension and Compression in the 3ph links acting on the tractor body at their forward ball positions. The supported cantilevered load (implement) only pushes downward on the hydraulics with its weight, but if that weight is centered far back those T&C numbers are huge.

You have to practically scramble and reorganize your brain to make sense of it. Heres a thread from way back that made some temporary progress:
Conversion Factor for 3PH load capacity

 

[DarkBlack]

Yes. That backtip resultant (a torque) is transmitted by Tension and Compression in the 3ph links acting on the tractor body at their forward ball positions. The supported cantilevered load (implement) only pushes downward on the hydraulics with its weight, but if that weight is centered far back those T&C numbers are huge.

You have to practically scramble and reorganize your brain to make sense of it. Heres a thread from way back that made some temporary progress:
Conversion Factor for 3PH load capacity

Every tractor and setup is different, depending on if the owner has height choices for the top link, and what length it’s adjusted to.
My post #28, takes out all the variables and complexity.

If you’re not looking for the reduction factor in lifting force referenced from the lower link pins, and instead want to know the factor based on an specification you know the location of is 24” behind the pins like ASAE S215.4, then simply replace the lower link pin height measurement I described, with a measurement 24” rearward on the implement.

The physics is still the same. If your boom pole lift point is raising more than your 3 point hitch reference point, then you have less available lifting force.
Yes, I agree , with the right upper link height, and length, an owner could create a boom pole setup where the lift point moves the same distance as the 3PH load spec point, but I’ve yet to see a boom pole mounted on a tractor that the owner didn’t have the upper link adjusted to create a greater vertical travel range than the 3PH movement.
There’s no free lunch.

 

[skramer360]

Just to answer a couple of questions. This is the log weight calculator I used.

Log Weight Calculator

This log weight calculator will help you estimate the weight of a freshly cut tree using its "green" density and volume.

www.omnicalculator.com

A bit more information that may help. The last time when I was able to lift a similarly sized log completely (not just one end) with this boom pole, I did not have the loader on the tractor. I was reading in the repair manual and I believe the hydraulic system bypass safety valve on the tractor has a higher rating than the loader bypass valve. So, this may be the answer to my question.

 

[SPYDERLK]

Just to answer a couple of questions. This is the log weight calculator I used.

Log Weight Calculator

This log weight calculator will help you estimate the weight of a freshly cut tree using its "green" density and volume.

www.omnicalculator.com

A bit more information that may help. The last time when I was able to lift a similarly sized log completely (not just one end) with this boom pole, I did not have the loader on the tractor. I was reading in the repair manual and I believe the hydraulic system bypass safety valve on the tractor has a higher rating than the loader bypass valve. So, this may be the answer to my question.

Sure could be. Turn it up a bit.