Position control vs. quarter inching valves

orangebluegreen · May 5, 2006

I would like to hear of others experiences with the two. All of my time on various machines with 3-points has been with an up/down type of valve with in the middle being neutral. From what I’ve read on TBN position control supposedly puts the three point at the same position every time you move the lever to the same number on the scale. If this actually works I would agree it’s a far better system, especially if you want to use it to control mower height.
I question however for the following reasons. I have tried out a few machines of varying major manufacturers that had position control and did not see the three point move to the position on the scale and the 3pt did not stop going down unless I pulled back some on the lever. The ones I tried moved the same as what I’m used to....that is move the lever almost all the way forward the 3pt goes down, all the way up it goes up. I did not observe it moving in sync with the lever on the position control models as I am hearing is supposed to be the case. I also tried a Kubota with ¼ inching. The name is rather misleading IMO, it brings one to believe the hitch will only move in ¼ inch increments when in reality it is dependant on how far apart the stops are set on the guide. If the stops are set wide apart it works the same as any other up/down valve I’m used to.

The point of this....
Is it worth pursuing a B2410 over a B7610/7510 for position control? The price of a 2410 was originally about $2000 higher for basically nothing more than position control. Looking at the parts manual it appears part number 6C070-36202 ASSY VALVE CONTROL is the only difference I can find between the two machines. At just over $400 for the valve, it would be a lot less to retro a B7610 than pursue a B2410 IMO. You wouldn’t have the nice numbered scale, but suppose that could be made easy enough. There is definitely a different part number between the B7610/7510 and the B2410, but...the B2410 has an extra rear hydraulic outlet there. The valves must be interchangeable because the B7510 DTN has position control. I also notice the higher numbers for 3pt lift are on the machines with position control and I’m not sure if it’s due to the valve or as it says in Kubota’s brochure for the 2410 “We’ve changed the link ratio and increased power by 28% over previous models” but that is unclear if due to hydraulics or link ratio (which I assume means mechanical leverage.)

In any case, it appears ill advised for Kubota to have used the supposed ¼ inching valve because it gives the competition something to claim they have K doesn’t. I can’t imagine the cost to K can be more than a few dollars.

DanR67 · May 5, 2006

OBG -

The "quarter inching" simply refers to the amount of 3PH height change with each bump of the 3PH Up/Down control lever. It has two mechanical detents - so when you bump the lever forward - for example - to lower the 3PH - if you move the lever from the center to the forward detent and back - the 3PH should have dropped @ 1/4 inch....

Granted - the two stops / detents have to be set correctly (they are adjustable). By "flexing" the 3PH Up/Down lever *away* from you (so when you are sitting in the seat - I mean out to the side of the tractor - ex. "3 o'clock") - you can simply bypass the detents / stops - and the 3PH will drop / raise very quickly.

With the "position control" on the 3PH - so once you set the height you want (ex. boxblade / tiller / plow etc.) your implement to engage the ground - the 3PH will automatically correct / adjust to maintain the same amount of engagement with the ground all while leaving the 3PH Up/Down lever in the center position. I would think a "scale" next to a PC 3PH lever would be completely arbitrary as far as actual digging depth - as each implement would touch the ground at a different point - but could imagine you should get repeatable results with the same implement if set to the same point on the scale....

As I understand it - there is an additional, mechanical "feedback linkage" with the position control - which performs the automatic Up/Down 3PH adjustment with respect to the angle between the tractor, the 3PH and the ground as you pass over bumps / irregularities. (Honestly don't know if you see the 3PH lever move though...)

With the quarter-inching setup - you have to manually / constantly make adjustments to maintain the digging depth - because otherwise the 3PH cylinder stays in the same position - but if the tractor goes over a high spot / through a low spot - the depth of the "cut" of the 3PH attachment will vary - unless manually compensation for.

Needless to say - if you are trying to level a large area - this will require a fair amount of concentration to maintain a consistent digging depth - and as I do find my 3PH control to be a bit touchy - I can imagine this would be a drag. I do have to "work" my 3PH lever when I'm using my 3PH snowblower on a stretch of gravel driveway - else it quickly turns into a "rock cannon"! /forums/images/graemlins/grin.gif

Clearly - if you plan to do extensive landscaping or tilling - then the position control is the way to go.

***************************

As far as the overal 3PH lift capacity - my guess is that the B2410 must have - primarily - a physically larger hydraulic cylinder ("increased power") - as otherwise the 3PH "geometry" ("link ratio") / mechanical leverage - would have to be moved out / back by *28%* - which would have to increase the length of the CUT+3PH lift arms.

It would be nice if Kubota offered the PC as an "option" / upgrade - but it wasn't a show-stopper for me. I was - in fact - originally hoping to buy a B2410 - simply because of the higher 3PH lift capacity - but my dealer didn't have any / plan on getting any - so I *settled* with the B7610 - but I have no complaints. /forums/images/graemlins/grin.gif

I'm sure Kubota - like everyone else - needs to take one product - and make some minor changes - rebadge / label it - and call it "deluxe" - so they can charge a heap more $$ for it! Just like with cars - you can only get certain options on certain models...

Hope that helps.

Dan

Bob_Young · May 5, 2006

I've got the same problems as you, orangebluegreen (Heh, same colors in my barn /forums/images/graemlins/smile.gif), but I'm coming at it from the other end. All my machines have position control, even the old JD40. I've been looking at the BX24 and the B7800 trying to figure out if 'Quarter-Inching' is something I could live with.

Basically, position control allows you to return a 3-pt. hitch implement to the same position by returning the hitch control to the same predetermined position on the control quadrant...at least that's how it works when its working right. With quarter-inching, as I understand it, you've only got 2 implement positions that you can positively return to; full up and full down. With position control, there can be several.

For example, I can back-blade snow off the paved area in front of my garage with the blade and control in the fully lowered or '0' position. As I reach the end of the pavement and pull snow into the overrun area, I must raise the control to the '3' position on the quadrant. If I time it right (there is some delay), the blade raises just the right amount to skim the snow off the grass without gouging ruts in the lawn. At the end of the run, I raise the control to the '8' position and the hitch raises the blade all the way up so I can head back for another run. If theres a hump in the pavement and running the blade fully lowered allows it to dig in, you can set the control at '1' or '1-1/2' for example, to raise the blade slightly and clear that area without causing damage. It's nice for bushhogging in areas where you suspect hidden trash or rocks.

My old Ford 4000 has two different modes that hitch can operate in. One is position control, the other is something like quarter-inching but without automatic return of the control to neutral. That thing used to give me fits until I found a valve under the seat that changed it to position control.

For small jobs, quarter-inching would probably work almost as well. For Ag machines that are worked all day long, position control probably saves a lot of operator fatigue and implement damage. It's kind of a 'big tractor' feature, if you will.

However, I do agree with you. Kubota should ditch this outmoded design if their competition has gone strictly position control.
Bob

Bob_Young · May 5, 2006

Dan, I think the feed back system you are referring to is position control with draft control sensing. Not all position control systems have draft control...in fact, most don't on small tractors. Draft control senses the load imposed on the tractor by the implement and, when it exceeds a certain point, responds by raising the implement until the load is reduced to normal. I believe it will also lower the implement, increasing engagement, if tractor load suddenly lightens. My Fords both have draft control, but I don't know how to set it up and use it.

Height/bump/irregularity sensing? Not aware of anything that does that. Would like to have it though.
Bob

cart99 · May 5, 2006

I've bush-hogged my 10 acres with both my neighbor's B7800 (1/4" valving) and my B3030 (position control). One of the biggest reasons I bought the B3030 over the B7800 is that I did not like the 1/4" valving. When I had to raise the brushhog to get over lumpy terrain, it was difficult to figure out where to lower it to again. It also seemed to leak-down when I went over bumpy terrain. I found myself constantly looking over my shoulder and fiddling with the height.

With the B3030, it's pretty much the same experience Bob Young described. If you need to move it, you can easily return it back to it's original position without looking back.

That being said, it is not nearly as advanced as DanR67 describes. The position of the implement does NOT automatically adjust. Position control keeps the implement in the same position relative to the tractor, not the terrain. Using a back blade, if you go over a hump with your rear tires, you get a nice corresponding hump in whatever your trying to level with the blade. With practice, you learn to compensate by working the control, but it's not a "set it and forget" type thing.

flusher · May 5, 2006

I just finished brush hogging 7 acres with a 4-ft KK hog on my B7510HST. It's flat grazing land with gentle rolls and it's rough in spots.

I found that I get the best results by setting the front of the mower a few inches from the ground and then closing the hydraulic valve (the knob under the seat). The hog then stays put with no leak down. I don't bother with the quarter-inching system.

jwstewar · May 5, 2006

When I was shopping for tractors I couldn't tell you a difference in what each was - and for that matter really didn't care. Figured both worked equally as well. Now that I've learned a little bit more and have a tractor with position control, I wouldn't ever by one w/o PC - well unless it was really, really cheap /forums/images/graemlins/laugh.gif

orangebluegreen · May 5, 2006

Some great feedback.

Dan, yeah I’m used to constantly working the lever, I ran a small dozer for many years grading the lots on houses we built. I think what you’re describing is draft control....sure would have been nice on my dozer.

( As far as the overal 3PH lift capacity - my guess is that the B2410 must have - primarily - a physically larger hydraulic cylinder ("increased power") - as otherwise the 3PH "geometry" ("link ratio") / mechanical leverage - would have to be moved out / back by *28%* - which would have to increase the length of the CUT+3PH lift arms. )

That’s what I thought originally as well, then read the comments about 28% and thought the same as yourself...they would have needed to move the leverage point back to gain increased lifting power. If so it would mean a 7510 would have different arms than a 2410, but not so. So far I’ve found no differences (doesn’t mean I might not be missing something.)
Comparing the 3pt pieces and hydro’s on a 7510 vs. 2410 I see no differences, they are apparently exactly the same parts. Only thing I can guess is maybe they raised the pressure in the position control valve because it is the only part number I see different.

B7510
YW176-00100 ASSY VALVE CONTROL

6C140-37304 ASSY PUMP HYDRAULIC

6C150-11603 ASSY HST

010 6C140-65200 ASSY ROD LIFT RH
020 6C040-65230 ROD LIFT UPPER RH
030 6C140-65240 ROD LIFT LOWER RH
040 6C070-65250 ROD LIFT MIDDLE
050 02172-50180 NUT
060 06613-10675 NIPPLE GREASE
070 6C140-65270 ROD LIFT
080 05122-51645 PIN JOINT
090 67156-34340 RING SNAP
100 05122-51240 PIN JOINT
110 05511-50425 PIN SPLIT

010 6C040-66010 PIN LOWER LINK
020 6C040-65120 BOLT
030 02018-50100 NUT
040 04512-60100 WASHER SPRING
050 6C040-65210 COMP.LINK LOWER
060 34150-37640 PIN SET
070 66204-65350 SPACER

B2410
6C070-36202 ASSY VALVE CONTROL

6C140-37304 ASSY PUMP HYDRAULIC

6C150-11603 ASSY HST

010 6C140-65200 ASSY ROD LIFT RH
020 6C040-65230 ROD LIFT UPPER RH
030 6C140-65240 ROD LIFT LOWER RH
040 6C070-65250 ROD LIFT MIDDLE
050 02172-50180 NUT
060 06613-10675 NIPPLE GREASE
070 6C140-65270 ROD LIFT LH
080 05122-51645 PIN JOINT
090 67156-34340 RING SNAP
100 05122-51240 PIN JOINT
110 05511-50425 PIN SPLIT

010 6C040-66010 PIN LOWER LINK
020 6C040-65120 BOLT
030 02018-50100 NUT
040 04512-60100 WASHER SPRING
050 6C040-65210 COMP.LINK LOWER
060 34150-37640 PIN SET
070 66204-65350 SPACER

orangebluegreen · May 5, 2006

( Basically, position control allows you to return a 3-pt. hitch implement to the same position by returning the hitch control to the same predetermined position on the control quadrant...at least that's how it works when it’s working right. With quarter-inching, as I understand it, you've only got 2 implement positions that you can positively return to; full up and full down. With position control, there can be several. )

That was my understanding also. The ones I tried out didn’t seem to make a difference between ¼”ing and position but there have been enough posts on TBN that say it does work. I’ll have to assume the reason I couldn’t tell any difference is there was no weight on the 3pt’s. It’s pretty hard to make one work how it’s supposed to without weight on it.

BTW...if TBN allowed longer screen names I would have added more colors. I'll change my ID after I've chosen a color.

orangebluegreen · May 5, 2006

( When I had to raise the brushhog to get over lumpy terrain, it was difficult to figure out where to lower it to again. It also seemed to leak-down when I went over bumpy terrain. I found myself constantly looking over my shoulder and fiddling with the height. )

Yes that’s what I’m used to using box blades, I find it normal because I’ve never used anything other, but if position control does what everyone says it does, then it must be convenient. I have also heard the solution Flusher mentioned as well being used by some folks. Seems to me the 3pt lever pin setup used on the B7510 Turf Special would work great for a rear mower also if the pins are strong enough.

I mentioned it in the last message of this thread....

Suspended VS Ground Contact MMM's?