Understanding draft control

[sixdogs]

Here's what draft control on a tractor is, what it does and why it does it. It's easy but there is a lot of confusion because the instructions are often poorly written.

1. "Draft control" merely causes the three point arms to maintain a constant amount of resistance, or "draft" as farm people call it. For example, if you had a grader blade on the back and drove though a tilled farm field, when the front wheels dipped into a hole, the rear blade would raise and dump a pile of dirt. Also the reverse when the front wheels hit a ridge and the rear blade will dig into the ground. Since rear linkage just naturally "floats", without the use of draft control, what happens is you add holes and humps and make a grading task worse.

2. Enter draft control. All it does is cause the rear linkage to not float but instead operate with a degree of resistance and you choose that amount with the levers. So when the front wheels hit a hole, the draft control tells the linkage and the rear arms and blade will then keep the same amount of resistance as though the front wheels were on flat ground. And the reverse; hit a hump with the front wheels and the draft control tells the rear arms to lessen resistance and keep the same amount as before hitting the hump.


3. That's all there is to it. The 3pt arms lever (position control) and draft lever are interrelated and you have to fiddle with both until you get what you want. In plowing, if you hit a front hole, the plow will lift and you won't have the depth of cut wanted. And the reverse if you hit a hump and get a too-deep cut. Plowing would be more, meaning more draft control needed.


*******


A. That's about it, short of experience. You could read 50 pages on how to ride a bike or instead learn by falling off twice. For me, I use draft control mostly with an 8' rock rake and sometimes a blade. Through repeated passes, I can leave a graded area so smooth and flat that strangers stop and take pictures. I need lighter draft control for this while plowing or cultivating would take more draft control.

B. Another practical example is using cultivators. You might be just cultivating along and suddenly bog down and nearly stall the tractor. We now know that's likely because the front wheels hit a small rise and caused the cultivators to sink in. With the use of draft control, kiss that issue goodbye.

C. For extra credit, look up Harry Ferguson and the so-called 3 pt and draft control "Handshake Agreement" with Henry Ford that went south. That caused the growth of Ferguson tractors, the eventual origin of Massey- Ferguson and then on to Agco. All of this because of Harry's innovation and development of draft control.

 

[oosik]

My Kubota M6040 has draft control. I used it ONCE with my single bottom moldboard plow. Too many large rocks in the particular field I choose.

I suppose it might come in handy when I use the rear blade on my driveway. I've found it a whole lot easier to just drag my LPGS.

 

[CausticUrbanCoast]

Here's what draft control on a tractor is, what it does and why it does it. It's easy but there is a lot of confusion because the instructions are often poorly written.

1. "Draft control" merely causes the three point arms to maintain a constant amount of resistance, or "draft" as farm people call it. For example, if you had a grader blade on the back and drove though a tilled farm field, when the front wheels dipped into a hole, the rear blade would raise and dump a pile of dirt. Also the reverse when the front wheels hit a ridge and the rear blade will dig into the ground. Since rear linkage just naturally "floats", without the use of draft control, what happens is you add holes and humps and make a grading task worse.

2. Enter draft control. All it does is cause the rear linkage to not float but instead operate with a degree of resistance and you choose that amount with the levers. So when the front wheels hit a hole, the draft control tells the linkage and the rear arms and blade will then keep the same amount of resistance as though the front wheels were on flat ground. And the reverse; hit a hump with the front wheels and the draft control tells the rear arms to lessen resistance and keep the same amount as before hitting the hump.


3. That's all there is to it. The 3pt arms lever (position control) and draft lever are interrelated and you have to fiddle with both until you get what you want. In plowing, if you hit a front hole, the plow will lift and you won't have the depth of cut wanted. And the reverse if you hit a hump and get a too-deep cut. Plowing would be more, meaning more draft control needed.


*******


A. That's about it, short of experience. You could read 50 pages on how to ride a bike or instead learn by falling off twice. For me, I use draft control mostly with an 8' rock rake and sometimes a blade. Through repeated passes, I can leave a graded area so smooth and flat that strangers stop and take pictures. I need lighter draft control for this while plowing or cultivating would take more draft control.

B. Another practical example is using cultivators. You might be just cultivating along and suddenly bog down and nearly stall the tractor. We now know that's likely because the front wheels hit a small rise and caused the cultivators to sink in. With the use of draft control, kiss that issue goodbye.

C. For extra credit, look up Harry Ferguson and the so-called 3 pt and draft control "Handshake Agreement" with Henry Ford that went south. That caused the growth of Ferguson tractors, the eventual origin of Massey- Ferguson and then on to Agco. All of this because of Harry's innovation and development of draft control.

Nice description of the sensing draft control. How about one for the non-sensing draft control?

 

[JimB77]

Here's what draft control on a tractor is, what it does and why it does it. It's easy but there is a lot of confusion because the instructions are often poorly written.

1. "Draft control" merely causes the three point arms to maintain a constant amount of resistance, or "draft" as farm people call it. For example, if you had a grader blade on the back and drove though a tilled farm field, when the front wheels dipped into a hole, the rear blade would raise and dump a pile of dirt. Also the reverse when the front wheels hit a ridge and the rear blade will dig into the ground. Since rear linkage just naturally "floats", without the use of draft control, what happens is you add holes and humps and make a grading task worse.

2. Enter draft control. All it does is cause the """"rear linkage to not float""" but instead operate with a degree of resistance and you choose that amount with the levers. So when the front wheels hit a hole, the draft control tells the linkage and the rear arms and blade will then keep the same amount of resistance as though the front wheels were on flat ground. And the reverse; hit a hump with the front wheels and the draft control tells the rear arms to lessen resistance and keep the same amount as before hitting the hump.


3. That's all there is to it. The 3pt arms lever (position control) and draft lever are interrelated and you have to fiddle with both until you get what you want. In plowing, if you hit a front hole, the plow will lift and you won't have the depth of cut wanted. And the reverse if you hit a hump and get a too-deep cut. Plowing would be more, meaning more draft control needed.

sixdogs
Please explain how a single acting(one way) cylinder or cylinders such as most farm tractors 3 pt hitches possess when at a height other than fully raised not float whether control is utilizing "draft control or no draft control".
Thanks Jim

 

[MossRoad]

Draft control doesn't have anything to do with the front tires dipping into a hole or riding up a hill. It works on flat ground as well. It only "cares" about the rear end of the tractor.

It works by sensing the load on the implement that's engaged in the ground. Pull a plow, box blade, or other implement into tough soil. That load causes the rear tires to spin, which digs a hole, which lowers the rear end of the tractor. When the rear end lowers, that tries to change the triangle angles that are formed between the 3pt arms, the implement, the top link, and the rear of the tractor. All that puts pressure on the rock shaft that the top link is connected to. The rock shaft operates a valve that raises the 3pt arms to try and maintain the proper angles in triangle. As the 3pt arms lift the implement out of the tough soil, that causes less resistance to the tractor. The tractor is able to climb out of the tire holes in the ground. The load on the top link pulls back, moving the rock shaft in the opposite direction, which lowers the implement back toward the pre-set location.

 

[Tinhack]

And to just make it more complex; Most tractors with draft control also have multiple top-link and sensing holes for the pin. The location of the pin determines how sensitive the draft will be or to lock it out entirely.

 

[Tinhack]

Oh yeah, did I mention the draft speed adjustment?

 

[LD1]

Think of draft control as maintaining a constant compression force on the toplink.

Some have different settings. some the settings are just choosing a different toplink hole.

With a plow or blade or anything that digs in the dirt on the 3PH, as you drive forward with the implement in the ground....the ground is trying to push backwards on the implement. This causes the implement to want to rotate around the lower pins and in turn it tries to compress the toplink.

Draft control is to sense this "compression" force of the toplink and want it to remain constant. Exceed watever "compression" force is desired and the 3PH will automatically raise the hitch to try and lessen that compressive force (lessen the draft load). Example would be plowing and hitting a patch of hard ground....or even as he eluded to...front tires go over a mound and the rear implement tries to dig in.

Whenever it senses too little compressive force it reacts and LOWERS the hitch to try and increase the draft load.

All of this draft mechanism like on old 8n fords were connected to a spring and rod. The different toplink mounting positions changed the leverage that the top-links compressive force had on the spring and rod....thus either making the draft control more sensitive or less.

This was great back in the day of plowing acres of field with an 8n and a 2-bottom....because you would never spin-out. How many people with our modern compact tractors that do plowing or pulling a rear blade are constantly fidgeting with your 3PH lever. Get too agressive of a bite and start loosing traction and you raise it the hitch a little to keep moving.....then lower it again when you need more bite. Thats sorta what draft control does automatically.

For me, I dont have draft and never had a want or need for it. When I am plowing my garden or my 2-acre corn plot....I want constant depth....NOT constant draft load. I have sufficient tractor to pull 3-14 plow. I dont want the plow deciding on its own that I am in a hard patch of ground and deciding it only wants to plow at 4-5" instead of my desired 7-8". I want my plow to maintain depth. And with a properly set plow.....it wont plow TOO deep. SO I just lower the lever ALL the way and go. The frot going over a bump or incline does NOT make the plow dig deeper if it is set right. And fronts dropping into a hole or depression....with the hitch in float it stays at depth

 

[oosik]

I've come to notice something about Owners Manuals. If they were written by people whose first language was YOUR first language - we would be a whole lot better off.

Just imagine an east African - bought his brand new Ford tractor - trying to comprehend his OM that's written in Simbutu.

And the more difficult it is to put into words - the more difficult it is to understand.

 

[RickB]

How about lower link draft sensing?

 

[CausticUrbanCoast]

I've come to notice something about Owners Manuals. If they were written by people whose first language was YOUR first language - we would be a whole lot better off.

Just imagine an east African - bought his brand new Ford tractor - trying to comprehend his OM that's written in Simbutu.

And the more difficult it is to put into words - the more difficult it is to understand.

Not sure some of us ever saw an owners manual for the old tractors we had.

They used to refuse to even give you parts pages so you could check assembly order. If the parts guy really liked you, sometimes they showed you the microfiche.

Draft sense is great for things like row tillers, mowers, rakes, and seed drills. As mentioned above, it has mixed use/purpose for subsoil implements.

The new version of draft sense and control (if you can afford it) is 3d gps positioning control, which does have applications for subsoil implements and is now heavily used in construction and road building. You set your position and it maintains that position despite what the surface is. It sure makes feilds flat now...

 

[RickB]

Not sure some of us ever saw an owners manual for the old tractors we had.

They used to refuse to even give you parts pages so you could check assembly order. If the parts guy really liked you, sometimes they showed you the microfiche.

Draft sense is great for things like row tillers, mowers, rakes, and seed drills. As mentioned above, it has mixed use/purpose for subsoil implements.

Draft control is most effective when used with ground engaging implements. Mowers aren't in that group.

The new version of draft sense and control (if you can afford it) is 3d gps positioning control, which does have applications for subsoil implements and is now heavily used in construction and road building. You set your position and it maintains that position despite what the surface is. It sure makes feilds flat now...

That's actually an advanced version of position control. Not at all related to draft control. These systems do not vary working depth from the surface because of the draft load.
This response is a great example of the common misunderstanding of the purpose and function of draft control.

 

[JimB77]

IMHO JD lower draft sensing if adjusted per tech manual operates much better than upper link draft sensing on upper link sensing best day. Major downfall is the requirement of the seals that will eventually LEAK OIL at the bottom of transmission case(hyd oil reservoir)!

 

[RickB]

IMHO JD lower draft sensing if adjusted per tech manual operates much better than upper link draft sensing on upper link sensing best day. Major downfall is the requirement of the seals that will eventually LEAK OIL at the bottom of transmission case(hyd oil reservoir)!

Lower link sensing is effective with semi mounted implements. Top link sensing is worthless with semi mount implements. Electronic draft control solves the leaking seals complaint (but introduces other potential concerns).

 

[wolc123]

Unless mud is an issue, I prefer to use my 1951 Ford 8n over my 2005 JD for plowing because it has draft control but the JD does not.

The front wheel assist on the JD trumps the position control on the 2wd Ford when mud is an issue.

 

[JimB77]

Lower link sensing is effective with semi mounted implements. Top link sensing is worthless with semi mount implements. Electronic draft control solves the leaking seals complaint (but introduces other potential concerns).

I'll take JD's newer style L/D shaft seals similar to what my 4255 has over electronically controlled anything. My 4255 with 11,500+ hrs showing on speed/hour meter. Many hours of 3 pt plowing & is on it's 3rd set of L/D seals. That doesn't include the baling of many 1000's of rd bales

 

[JimB77]

Unless mud is an issue, I prefer to use my 1951 Ford 8n over my 2005 JD for plowing because it has draft control but the JD does not.

The front wheel assist on the JD trumps the position control on the 2wd Ford when mud is an issue.

I was taught never to plow muddy soil.

 

[LouNY]

IH uses lower link sensing thru a strain gauge type arrangement no leaks to worry about.
Even so I seldom use it as in our heavy tillage, chisel plows and trailing disc in extremely stony
and compacted soil is right on the verge of traction lose. Because of the stone we run slow and I can
trim my work depth without trying to rely on draft control. I'm in second or third gear watching back all the time,
it's much easier to go slow and stay in the seat instead of have to get out and replace clamps and u bolts
and wrestle with those heavy shanks.
We have had draft control on tractors since the late 50's and very seldom have we been pleased with the results
of it.

 

[mred2]

Watch the old video. It explains the first draft control.

 

[wolc123]

I was taught never to plow muddy soil.

I don’t always have that option on my mucky bottomland farm. Some years, if waited for all the wet spots to dry completely, I wouldn’t have time for crops to mature before the frost.

A little mud pretty much brings my old Ford to a stop on the plow, but my 4wd JD will pull it right thru standing water without even slowing down.

This spring was pretty dry, and I got it all done with the Ford. I am interested to see what next year brings.

My original, 1951 furrow-side rear rim rusted through right after I finished plowing this spring. I replaced it, but did not load the new one with calcium.

It always pulled that 2 x 12 plow like a dream, on non-muddy ground, with two loaded rears. I have no clue how it will do with just one.

I have another new rim, but I am not going to change that side until it also rusts thru.