The Descriptive Process

[rwoods]

I am getting use to steering with my feet on the 750B. The brake pedal in the middle is frozen, so I still find myself trying to clutch with the left pedal especially after running the tractor loading trailers. I don't like that the throttle is pushed forward to speed up, but the transmission lever is pulled back to speed up. The two track drives also aren't equal. Right side is much stronger than the left. Probably poor maintenance or something out of adjustment. It travels straight but put it under a load while turning and it is very noticeable. The Deere 700 I pushed dirt with for about an hour one day was really sweet. I would take it any day over the 750. It was new, however.

I don't recall the D6 that I have moved a few times to have been configured like you described the D7, but it has been a couple of years since I have been in it. If I recall correctly, it was pretty much like the Deere 700 - steering and transmission on same left-hand control. Or to a CAT man should I say the Deere controls were like the CAT.

I will keep you updated.

Ron

 

[catbuster]

I am getting use to steering with my feet on the 750B. The brake pedal in the middle is frozen, so I still find myself trying to clutch with the left pedal especially after running the tractor loading trailers. I don't like that the throttle is pushed forward to speed up, but the transmission lever is pulled back to speed up. The two track drives also aren't equal. Right side is much stronger than the left. Probably poor maintenance or something out of adjustment. It travels straight but put it under a load while turning and it is very noticeable. The Deere 700 I pushed dirt with for about an hour one day was really sweet. I would take it any day over the 750. It was new, however.

I don't recall the D6 that I have moved a few times to have been configured like you described the D7, but it has been a couple of years since I have been in it. If I recall correctly, it was pretty much like the Deere 700 - steering and transmission on same left-hand control. Or to a CAT man should I say the Deere controls were like the CAT.

I will keep you updated.

Ron

Dozer controls have varied wildly over the years. Even the bigger tractors are totally different model to model. Cat’s D6M-D11R used three different drive and steer controls in the same generation of diff steer machines.

The hystat machines, and even more recent electric drive tractors, are much more uniform in drive controls. I can’t lie, I don’t like the combined controls on a dozer. On a skid steer or crawler loader they can’t be beat, but continuous straight line work I’ll sometimes find myself swerving a little as I hit bumps side to side. I find that interesting, especially given that a lot of the small hystat machines are built for fine, finish work.

The problem with these systems is that they work well for proportioning hydraulic flow to accomplish the movement of the tractor, they’re not as adaptable for direct drive where the mechanical system is multiple times more complex between a powershift transmission (complex enough already), torque converter (when should it lock up?), and steering with the differential or steering clutches.

A D7R-series after that H model-would be the first year of the Cat paddle steer. It’s a system where pushing or pulling one lever did your steering, twisting that same lever did your directional control (away-forward & towards-reverse) and it had two buttons for gear changes. Cat still uses it on the D5-D8 tractors. It’s fine, but I prefer the U shift & lever steer. It just goes right back to a datum of straight because your hands let go of the steer controls.

Either way, direct drive is more responsive, and makes for a better handling tractor. It’s a more efficient and durable system. The advantage to hystat is the literally infinite range of speeds available for fine work at full power, which is advantageous as it allows you to have a broad variation of the rate you spread material & you can spend less time setting things to a fine grade.

As far as application, Cat & Komatsu run direct drive for their big tractors, as did International/Dresser and Fiat-Allis before they were bought out. Deere dozers are all hystat, up to about a D8 size, and Liebherr builds a hystat dozer that’s about the size of a D10 or Komatsu D375. If you look at the market leaders in the big dozer market it should be obvious which system works better-and the PR776 has 150 horsepower over a D10 or 375, but has the same blade capacity, which in my mind puts the D10 at ~20% more efficient.

Wow, that was a lot of rambling. About dozer controls and drivelines.

 

[madhatte]

Looks to be military surplus. I have never regretted getting something on the cheap from the gov. They do buy from the cheapest bidder, yes, but the bids are accepted based on the contract. Generally they know what they want regarding machinery.

 

[crazyhorse666]

ironically they were stealing the semi feral cats food this morning...

the story is that Grey Jays "camp robbers" are the ghosts of dead loggers, they are mischievous, fearless, and will pick up anything that looks even remotely valuable and hide it from you, not necessarily in their nest, just where you will never ever find it, there is almost always a group of 3 or more 2 to create mayhem, 1 for a look out, if there is more then 3 there is almost always a leader (the real trouble maker)

They are not large birds, littel bigger then a standard robin, soft grey with white patches and in winter have an almost fuzzy appearance, they are friendly even in the wildest of wildernesses, which is just a trick to get close to you and steal your gloves. The will work with "blue" jays i.e. Steller's Jays, but probably only as a long game con to get their vote and take over their feeding spots.

Kea's don't usually bother with subtlety. They know they're smarter than the average person so just take what they want.



They also seem to like screwing with people just for fun.





I've met plenty of people who would likely fail that test.
I think the presenter might as he doesn't seem to understand the difference between a Kiwi and an Aussie.

 

[rwoods]

Dozer controls have varied wildly over the years. Even the bigger tractors are totally different model to model. Cat’s D6M-D11R used three different drive and steer controls in the same generation of diff steer machines.

The hystat machines, and even more recent electric drive tractors, are much more uniform in drive controls. I can’t lie, I don’t like the combined controls on a dozer. On a skid steer or crawler loader they can’t be beat, but continuous straight line work I’ll sometimes find myself swerving a little as I hit bumps side to side. I find that interesting, especially given that a lot of the small hystat machines are built for fine, finish work.

The problem with these systems is that they work well for proportioning hydraulic flow to accomplish the movement of the tractor, they’re not as adaptable for direct drive where the mechanical system is multiple times more complex between a powershift transmission (complex enough already), torque converter (when should it lock up?), and steering with the differential or steering clutches.

A D7R-series after that H model-would be the first year of the Cat paddle steer. It’s a system where pushing or pulling one lever did your steering, twisting that same lever did your directional control (away-forward & towards-reverse) and it had two buttons for gear changes. Cat still uses it on the D5-D8 tractors. It’s fine, but I prefer the U shift & lever steer. It just goes right back to a datum of straight because your hands go off the steer controls.

Either way, direct drive is more responsive, and makes for a better handling tractor. It’s a more efficient and durable system. The advantage to hystat is the literally infinite range of speeds available for fine work, which is advantageous as it allows you to have a broad variation of the rate you spread material & you can spend less time leveling things to a fine grade.

As far as application, Cat & Komatsu run direct drive for their big tractors, as did International/Dresser and Fiat-Allis before they were bought out. Deere dozers are all hystat, up to about a D8 size, and Liebherr builds a hystat dozer that’s about the size of a D10 or Komatsu D375. If you look at the market leaders in the big dozer market it should be obvious which system works better-and the PR776 has 150 horsepower over a D10 or 375, but has the same blade capacity, which in my mind puts the D10 at ~20% more efficient.

Wow, that was a lot of rambling. About dozer controls and drivelines.

Thanks for the lesson. I have never done any true grading with a dozer - mainly just pushing dirt from point A to point B.

I get the move to fluid, but I like mechanical connections generally. Army swapped the manual transmission for automatics because new recruits couldn't drive manuals - so my truck (the last rebuild of the M35 series) has an Allison. It has no park position, just the hand brake which translates to you can't park it anywhere without chocks - an impossible task at times without a helper. Also, you can't roll start it. My little Deere has a hydraulic clutch that is disengaged when it isn't running or the fluid level is too low. No roll starting it either. Impossible to load it with low fluid - goes so far up the ramps and then disengages.

Ron

 

[catbuster]

Thanks for the lesson. I have never done any true grading with a dozer - mainly just pushing dirt from point A to point B.

I get the move to fluid, but I like mechanical connections generally. Army swapped the manual transmission for automatics because new recruits couldn't drive manuals - so my truck (the last rebuild of the M35 series) has an Allison. It has no park position, just the hand brake which translates to you can't park it anywhere without chocks - an impossible task at times without a helper. Also, you can't roll start it. My little Deere has a hydraulic clutch that is disengaged when it isn't running or the fluid level is too low. No roll starting it either. Impossible to load it with low fluid - goes so far up the ramps and then disengages.

Ron

Fire apparatus have gone entirely to Allison automatics over the last 20 years, to the end that the only transmissions NFPA will rate are the 3000EVS and 4000EVS. They have no “park” either. The trans goes to neutral and the parking brake is applied. Every heavy-duty truck with an automatic transmission, from on highway dumps, fire apparatus up to off highway haul trucks are like that.

Of course, I have strong feelings about NFPA policies, like limiting fire truck top speeds to 68 miles per hour or 60 for a GVWR over 50,000. Or really, all of 1901 for that matter. Lots of over-protective pansy-ass stuff going on. I’m too young to be feeling that way. And I’m usually the guy saying safety rules are written in blood.

Anyway, that D7 has a torque converter, with no clutch, like an automatic transmission. In a high load, lugging application like you’ll see in a dozer, it acts as a torque multiplier and prevents a stall. Differential steer is actually a pretty ingenious design if you ever want to take the time to read the design & principle of the thing. I am probably not capable of giving an explanation that would cover it clearly enough, but it’s not exactly how you would think, or straightforward.

 

[northmanlogging]

Fire apparatus have gone entirely to Allison automatics over the last 20 years, to the end that the only transmissions NFPA will rate are the 3000EVS and 4000EVS. They have no “park” either. The trans goes to neutral and the parking brake is applied. Every heavy-duty truck with an automatic transmission, from on highway dumps, fire apparatus up to off highway haul trucks are like that.

Of course, I have strong feelings about NFPA policies, like limiting fire truck top speeds to 68 miles per hour or 60 for a GVWR over 50,000. Or really, all of 1901 for that matter. Lots of over-protective pansy-ass stuff going on. I’m too young to be feeling that way. And I’m usually the guy saying safety rules are written in blood.

Anyway, that D7 has a torque converter, with no clutch, like an automatic transmission. In a high load, lugging application like you’ll see in a dozer, it acts as a torque multiplier and prevents a stall. Differential steer is actually a pretty ingenious design if you ever want to take the time to read the design & principle of the thing. I am probably not capable of giving an explanation that would cover it clearly enough, but it’s not exactly how you would think, or straightforward.

seems to me that every once in awhile especially in wildfire situations, that exceeding 68mph could be the difference between boy that was close, and oh thats hot...

 

[rwoods]

Can’t go rushing to a fire in a M35A3 though I have seen several used as brush trucks - 56 mph at max rpms.

I’ll check out the differential steering. Many years ago, I read of high speed designs for the military that uses multiple diffs. I can’t remember the exact configuration, but it prompted me to think about using three open diff design on a common plane. Power to center diff to short axles, each to the axle side of two outboard diffs with outer axles to the load. Hydraulic motors on the pinion shaft of each outboard diff. To steer the hydraulic motors turn the pinions, one speeding up the load axle and the other slowing the opposite load axle. I believe the weak point is the stress on the spiders. Not having any machinist or welding skills, I thought of using existing self contained automotive diffs. At the time the only suitable diff available to me was from a Corvette or from a similar swing arm suspension so I never built one to see if it would work. Lots of diffs available now. One day I may just build one to see if it will work. Nice buggy drive if it does. I don’t think it would be truly proportional based upon the turning radius, but I believe it will turn.

Ron

 

[rwoods]

Just watched a short video explaining CAT’s patented differential steering. Appears to be the same basic concept as I described but using outboard planetary gears sets instead of outboard ring and pinion gear sets. I would think their design would be a lot stronger. Either way the concept is so simple, you have to wonder why it wasn’t laid out as a design in the early 1900s even though the necessary components were not then available.
Ron

 

[Jhenderson]

Fire apparatus have gone entirely to Allison automatics over the last 20 years, to the end that the only transmissions NFPA will rate are the 3000EVS and 4000EVS. They have no “park” either. The trans goes to neutral and the parking brake is applied. Every heavy-duty truck with an automatic transmission, from on highway dumps, fire apparatus up to off highway haul trucks are like that.

Of course, I have strong feelings about NFPA policies, like limiting fire truck top speeds to 68 miles per hour or 60 for a GVWR over 50,000. Or really, all of 1901 for that matter. Lots of over-protective pansy-ass stuff going on. I’m too young to be feeling that way. And I’m usually the guy saying safety rules are written in blood.

Anyway, that D7 has a torque converter, with no clutch, like an automatic transmission. In a high load, lugging application like you’ll see in a dozer, it acts as a torque multiplier and prevents a stall. Differential steer is actually a pretty ingenious design if you ever want to take the time to read the design & principle of the thing. I am probably not capable of giving an explanation that would cover it clearly enough, but it’s not exactly how you would think, or straightforward.

When our fire dept bought our last Pierce engine we had to sign a waiver to get the max speed limiter increased. It’s pretty bad when you’re responding on the highway and can‘t keep up with regular traffic.

 

[catbuster]

Just watched a short video explaining CAT’s patented differential steering. Appears to be the same basic concept as I described but using outboard planetary gears sets instead of outboard ring and pinion gear sets. I would think their design would be a lot stronger. Either way the concept is so simple, you have to wonder why it wasn’t laid out as a design in the early 1900s even though the necessary components were not then available.
Ron

Don’t quote me on it-but I believe some of the German tanks in world war two used a variation of diff steer. That would be the earliest iteration I can think of. Also, the design for a differential steer you brought up in an earlier post sounds similar to something International Harvester did with their later tractors. If you can pull up a service manual or set of drawings for something like a TD-25C it may help you out.

It really is (sorta) simple, but I would guess when the world of tracks ran on steering clutches it would require some seriously out of the box thinking. I mean, the D10 and D11 still use standard clutches and brakes.

 

[Woodslasher]

Kea's don't usually bother with subtlety. They know they're smarter than the average person so just take what they want.



They also seem to like screwing with people just for fun.





I've met plenty of people who would likely fail that test.
I think the presenter might as he doesn't seem to understand the difference between a Kiwi and an Aussie.

A Kiwi is a fruit and an Aussie is a guy from down under, right?

 

[madhatte]

Of course, I have strong feelings about NFPA policies, like limiting fire truck top speeds to 68 miles per hour or 60 for a GVWR over 50,000. Or really, all of 1901 for that matter.

You will be interested to hear that NFPA 1901 and 1906 (Wildland apparatus) and another to do I think with aviation are about to all be rolled into the new NFPA 1900 covering all in a single guidance. I think the publication date is to be later this year. I called those guys a little bit ago because we're supposed to be transitioning to EV's over the next few years and there is no guidance on that at all, not NFPA, not NWCG, none. I sent a note up the chain seeking guidance and have not gotten any response at all yet.

 

[rwoods]

Despite the thorough tutorial from catbuster, my inexperience showed itself in a rather embarrassing way today. It seems no one at the range has a key to the D7 and the grounds are looking a little unsightly with the inmates mowing around it and the other parked equipment including all my stuff, so being a proud owner of a CAT key, I fired up the 7 and drove it around a bit. After parking it, I turn the key to off and it kept running. I thought given the fancy dash that it would have a solenoid to cut the fuel. I looked everywhere for a switch or a mechanical shut off but couldn't find one. Turned the master switch off - still running. Didn't make sense that a solenoid would get stuck holding a valve open, but I have had all kinds of surprises with old military stuff. Range boss was at a loss as well. I called one of my equipment friends who told me what to do - otherwise it would probably still be idling.

First ride impressions, reverse seemed to be pretty fast, a feeling enhanced by my unfamiliarity and the high perch. Steering was great, but the tracks tore up the ground significantly more than the smaller Deere 750B. Other than moving a D6 around a bit, I have not run a high drive so maybe this is typical - at certain forward speeds the tracks had a wave action going on that was a bit disconcerting. Nonetheless, I think with a little practice I could get comfortable. No left steering pedal to be clutched in error. Decelerator worked great as opposed to the Deere's center pedal which now that it has loosen up functions more like a delayed on and off switch than a brake.

Ron

 

[catbuster]

if the tracks are moving up and down a bunch, measure the slack. The spec is 2” off a straight edge across the front idler to the first roller to the top of the lowest grouser bar. High drive machines do this-think about how far that track has to fall off the sprocket to get to the roller.

A D7H weighs 50 to 55,000 pounds depending on the setup (blade, ripper, winch, pad size). It’s kinda like the Stihl 046 of bulldozers, a borderline production class machine, which is to say that somebody without a lot of seat time and a good feeling in their butt, plus some space to run it so they don’t have to steer quickly, is going to make a mess.

I want to play with Cat’s current D7 offering (265 horsepower at 65,000 pounds) but right now I was told I’d have to order a new one, and that’s expensive. Given that I’m not in that industry anymore, it would be a little senseless as well.

 

[rwoods]

I didn’t measure anything but the tracks appear taut.

I won’t be taking it up the hill or in the woods. If I had some flat ground, I would be all over it. As you would expect it appears to be a well thought out machine.

Ron

 

[catbuster]

I got up at 4:30 this morning and the heat index was already 90…



I don’t consider myself a wuss, but I mean… Heat indices have been up in the 110 range and aren’t forecasted to drop out until the weekend.

 

[rwoods]

It is cooler here at the beach in FL than it is back in Tennessee.

Not much of a beach guy so I have been spending my time looking for old small JD crawlers. Light enough to tow behind my pickup but stout enough to drag tree length stems. I found a few 440s with 2/53 DD. 500# more pull than the JD putt putts, but I am not sure the neighbors can handle the noise. Not sure I can either.

Ron

 

[northmanlogging]

It is cooler here at the beach in FL than it is back in Tennessee.

Not much of a beach guy so I have been spending my time looking for old small JD crawlers. Light enough to tow behind my pickup but stout enough to drag tree length stems. I found a few 440s with 2/53 DD. 500# more pull than the JD putt putts, but I am not sure the neighbors can handle the noise. Not sure I can either.

Ron

them ole 2-53 destroits aren't all that loud, Johny deere also has some skookum mufflers that go with em.
That said, if they didn't have a destroit I'd be more inclined to get one my self.

 

[rwoods]

Don’t encourage me, NM. I was hoping for more cold water to be thrown on my thoughts of a toy crawler.

Nebraska tests for the 440 - DD drawbar pull is a tad over 7000# right at its weight. Gas pulls around 6500#, about 400# under its weight. 1010s start gaining weight through the 350s; all too heavy for my truck and trailer.

420C or 430C would be easier to tow as they are really light - but the transmission case is probably not tough enough for the stresses I would put on it.

My dad had a 1958 420w wheel tractor with a 5 speed and directional reverser which he bought new. Redline was around 1800 rpms. It did a lot of work for a 26hp tractor. It was still humming when he sold it after 25 years of use.

Ron