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Different scrapers - educate me Options · View
wayne87
Posted: Tuesday, July 31, 2018 10:50:03 PM

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Joined: 5/5/2003
Posts: 320
Location: houston
So after watching a great video of the new Volvo A60H pulling a K-Tec scraper it got me to wondering, what determines which variety of scraper a contractor would use? When would it be better to use an articulated farm tractor with a pull pan vs a converted ADT with a pull pan vs a dozer with a pull pan vs a regular scraper? I could see the dozer advantage with traction and the regular scraper advantage on very hilly terrain, but what are the other factors? I wouldn't think an A60H pulling two K-Tecs is a whole lot less of an outlay than purchasing a 651 scraper for instance. Those in the know, please let me know...
kcmtoys
Posted: Wednesday, August 01, 2018 4:03:42 AM

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Joined: 4/3/2003
Posts: 1,597
Location: Rockford,IL.
As I have observed as a lowboy driver, farm tractors and converted ADT's with K-Tec type pans are used for black dirt and loose sandy soil. Motor scrapers (say a 627) are used where some speed is needed for a longer dump run (highway or landfill operation) and heavier clay conditions, sometimes using a pusher tractor to load. A Cat pull tractor and pan (like a Cat D8 and Rome 89 Pan) are used for shorter runs where there is heavy brown or blue clay to be moved. Whistle Ken









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Mr. Scholz
Posted: Wednesday, August 01, 2018 1:32:41 PM
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Joined: 7/14/2008
Posts: 103
Location: Germany, CE
Hello Wayne,

it is just a guess, but I think the farm tractor and ADT pulled version of scrapers is much more affordable reguarding the purchase price than a classic motor scraper. Plus, the first two can be adjusted to the job size by adding or removing scraper units. So they offer a lot of flexibility to the contractor.

On the other hand, I can imagine that a motor scraper like a CAT 631 can be used under circumstances much harder and abusive then ADT or farm-tractor pulled scrapers. CAT even offered the 641 SA (Special Application) - a scraper exclusively manufactured for loading ripped rock. Here you need a machine with alot of metal to withstand all the punishment during loading. I have heard that a factory-fresh 657 can cost almost 2 million bucks. You have alot of steel, two engines, two automatic trannies, 4 planetary wheel drives, the gooseneck suspension system and on and on....

Imagine a CAT 657 pushed by two or three D9s - you have well over 2.000 HP and tremendous traction by four huge tires and three pairs of tracks. A payload of more then 65 tons is loaded in 20-30 seconds. I doubt that the farm-tractor/ADT pulled version will ever reach such productivity. But in lighter going, maybe even where ground pressure is an issue, ADT/farm-tractor pulled scrapers still offers you all the advantages of a self loading, hauling and dumping earth mover.

And then there is the track-type tractor pulled scraper as they are so popular in the UK. I think that is because in the UK, you have a lot of rain and mud and a well populated island. So quite short hauling distances where the lower speed of a track-type tractor just doesn't matter so much.


Hope this helps!

Max
Basketball Man
Posted: Saturday, August 04, 2018 1:39:36 PM

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Joined: 12/30/2008
Posts: 3,424
Location: Good ol' Indiana
It all comes down to what material you are moving and what you jobsite is like.

Pull pans work great in large flat areas, stripping topsoil, building building pads in flat areas. If you are building a pad for a warehouse in a corn field-I would get some tractors with pull pans. I have never been around the converted ADT's but I would guess they have similar strengths to the tractor pull pans?

Conventional 2 axle scrapers are expensive buy, and operate. However in hard clays, light rock, sand the conventional scraper does perform. Like others have said when you have hills to climb it is tough to beat a twin engine scraper. The last benefit to two axle scrapers is their tight turning radius.

The big enemy of the scraper all together is mud. (The exception might be dozer pull pans) None of them get along with it. That is where the ADT's and excavators can maybe buy you some more working days.

-Ethan
Collection 8/2/2016
For more of the Diorama and my collection: On Facebook or On YouTube
CatD11T
Posted: Sunday, August 05, 2018 12:50:44 AM

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Joined: 12/16/2009
Posts: 607
Location: Surprise, AZ
I work for a mass excavation company in Arizona. Pretty much all we do is move dirt with scrapers, building subdivisions, solar farms, mines, and commercial developments. Scrapers are our bread and butter.

Here, pull pans with ag tractors and ADT's are really only used in soft material (but not totally dry) and long hauls from cut to fill (especially with ADT's).

Paddle wheels (623, 613) are used for balancing and finish work. They can cut accurately to the hundredth of a foot. Paired with a grader, they can finish 6000 square yards a day.

Single engine scrapers (631, 651) are used in hard material. We push them with D10's. Using a pushcat allows the traction of the dozer to transfer into force on the scraper bowl which will load ripped or blasted rock (or kaliche, which is super hard dirt, almost like concrete) 100 times faster than a dual engine system. They're pretty gutless, so short and flat hauls from cut to fill are a necessity. They also get beat up way more than a dual engine, so often contractors will use older machines and run them until the maintenance costs are higher than the money we make.

Dual engine scrapers (637, 657) are used where the material can be loaded quickly and the haul roads might be longer or uphill. In push/pull, a 657 pair is unbeatable in terms of raw earthmoving power. For example, we used a fleet of them to dig cells for the major landfills around here. 637's will usually be used alongside 631's but in another part of the cut, where the material is softer and self loading is more feasible. They're also more maneuverable than single engine scrapers because of the terrain they can handle.

Hope that's useful!

-Adam
Mr. Scholz
Posted: Sunday, August 05, 2018 12:50:10 PM
Rank: Advanced Member
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Joined: 7/14/2008
Posts: 103
Location: Germany, CE
Thanks Adam,

now I've learned a lot from your input. Born in 1982, I'm just to young to have wittnessed some scraper-action in real life. There was a lot of knowledge about scrapers in Germany, as most of our highway net, airports and what-not was constructed with dirt pans. But since the 1980ies, earthmoving has swapped over to excavators and ADTs over here.

I was lucky enough to meet some of the old blokes who shared their stories about scrapers with me. And there are some pretty decent, in-depth civil engeneering books about scrapers here. Thank you for sharing your experience.

Adam, how do you train your scraper operators? Do they have to climb up the ladder starting with dump trucks and loaders and such? Or do you have a training school/site? Many scraper operators here in Germany learned "on the flight", some where sitting on the fenders of the tractor part watching an operator who knew the tricks... That was back in the 50ies/60ies. An absolute no-go now, of course.

Cheers
Max
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