3 PT Lift Questions

[Dranrab]

I am the new guy with lots of questions. I have done a good bit of reading and am still uncertain of the answer to several questions.

Why does 3 point hitch lift capacity matter? Aren't most implements that are chosen to size out well with a tractor well within the lift rating of the 3 PT?

Does a disc do its work via its inherent weight, or does the 3 PT exert downward force to help the implement dig?

 

[atsah]

There are light duty, medium duty and heavy duty implements in the same size, so the 3 point hitch lift capability is important. 3 point hitches do not have down pressure, the weight of the implement is important and works under it's own weight....

A disc will have an area on top of it to add weight to it to drive it further into the ground..

 

[jeff9366]

There are light duty, medium duty and heavy duty implements in the same size, so the 3 point hitch lift capability is important. 3 point hitches do not have down pressure, the weight of the implement is important and works under it's own weight....

Y E S

Implement weight is one factor. Grain Drills are heavy implements, often taxing lift capacity of compact tractors. Sometimes I pull 2" - 3" trees out of MOIST ground with chains connecting the stump to both Lower Links equally. Cannot do this will FEL; the rear wheels lift. Sometimes one blunders upon a used, bargain priced implement just a little heavier than optimum for tractor width. Nice to have a margin of 3-PT. lift capacity in this scene.

Implement weight is another factor. Long implements, such as mounted Disc Harrows and Bush Hogs place greater effective load on Three Point Hitch due to leverage.

A disc will have an area on top of it to add weight to it to drive it further into the ground..

I have great respect for Atsah's posts but I disagree in this case.

1) The front gangs of a mounted Disc Harrow are the cutting/penetration gangs, which throw dirt OUT. Penetration is properly increased by increasing front gang angles, which also increases draft force resistance.
The hitch tower is in the way of adding weight to the front gangs.

2) The rear gangs of a mounted Disc Harrow are the wider, smoothing gangs, which gather dirt IN.
If you add weight to the rear, your ground will be needlessly rough and there is usually a fat windrow/mound after the harrow, which is a leveling implement.

Rear gangs are adjusted less aggressively, usually two increments less aggressively than front gangs, but trial and error. If adjusted "flat" rear gangs replicate thin wheels rolling over the ground, gathering no dirt, doing no leveling.

Buy enough tractor. Buy enough Disc Harrow.

It takes 45 pounds of total mounted Disc Harrow weight bearing on each "disc" to smooth/level in two passes in most soil; one pass in moist soil in reasonable tilth. Generally speaking 45 pounds/disc means mounted Disc Harrow with "discs" 20" in diameter.


MORE: https://www.tractorbynet.com/forums...ing-three-point-hitch-mounted.html?highlight=

 

[jeff9366]

Does a disc do its work via its inherent weight, or does the 3 PT exert downward force to help the implement dig?

Weight and gang angle adjustment.

One of Newton's Laws: For every action, opposite reaction. Hitch down pressure would lift tractor rear wheels, decreasing traction.

 

[atsah]

Y E S

Implement weight is one factor. Grain Drills are heavy implements, often taxing lift capacity of compact tractors. Sometimes I pull 2" - 3" trees out of MOIST ground with chains connecting the stump to both Lower Links equally. Cannot do this will FEL; the rear wheels lift. Sometimes one blunders upon a used, bargain priced implement just a little heavier than optimum for tractor width. Nice to have a margin of 3-PT. lift capacity in this scene.

Implement weight is another factor. Long implements, such as mounted Disc Harrows and Bush Hogs have greater effective load on Three Point Hitch due to leverage.




I have great respect for Atsah's posts but I disagree in this case.

1) The front gangs of a mounted Disc Harrow are the cutting/penetration gangs, which throw dirt OUT. Penetration is properly increased by increasing front gang angles, which also increases draft force resistance.
The hitch tower is in the way of adding weight to the front gangs.

2) The rear gangs of a mounted Disc Harrow are the wider, smoothing gangs, which gather dirt IN.
If you add weight to the rear, your ground will be needlessly rough and there is usually a fat windrow/mound after the harrow, which is a leveling implement.

Rear gangs are adjusted less aggressively, usually two increments less aggressively than front gangs, but trial and error. If adjusted "flat" rear gangs are thin wheels rolling over the ground, gathering no dirt, doing no leveling.

Buy enough tractor. Buy enough Disc Harrow.

It takes 45 pounds of total Disc Harrow weight bearing on each "disc" to smooth/level in two passes in most soil; one pass in moist soil in reasonable tilth. Generally speaking 45 pounds/disc means mounted Disc Harrow with "discs" 20" in diameter.


MORE: https://www.tractorbynet.com/forums...ing-three-point-hitch-mounted.html?highlight=

You could very well be correct, my only experience with a harrow is an old drawbar pull harrow that my father use to install pieces of railroad track on top of it to make it work, I figured them to be the same but maybe not.. He may have only put the track on the rear, 50 years ago so I don't recall..

 

[jeff9366]

A drawbar disc transfers no implement weight to the tractor. All the DDH weight is on the pans. So weight on front of a DDH (no hitch tower) probably is effective and would not produce windrow.

 

[LouNY]

A drawbar disc transfers no implement weight to the tractor. All the DDH weight is on the pans. So weight on front of a DDH (no hitch tower) probably is effective and would not produce windrow.

I'll have to disagree with you on that statement, apparently you have never worked with drawbar tillage implements.
It is hard to see in this picture but draw bar discs have an adjustable hitch height and I guarantee that you can get tractor loading from them.
You pop off with lots of knowledge sounding information which at times is incorrect.

As does the drawbar pulled chisel plows the hitch is adjustable to get your tillage implement level so it will work correctly, the angle of attack on a set of tandem disc is to set how aggressively you wish to have them stirring up the soil, the weight that can be added to a set of disc is to increase the depth of penetration.
That weight can be evenly distributed or biased to the front and the hitch adjusted to pull them level.