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duck walking, what are the causes an what ways do you deal with it?

still learn'n

Senior Member
Joined
Feb 6, 2012
Messages
455
Location
Kansas
I would have to look might have some of the hydraulic but we haven't found a way to put them on Deere pans there isn't enough room! Not sure I have any of the bolt on! Deere made some at one time but don't know if they still do but don't see that they would work very well!! I will see if I have any pics
 

Scrub Puller

Senior Member
Joined
Mar 29, 2009
Messages
3,481
Location
Gladstone Queensland Australia
Yair . . . I have been following this thread with interest.

My memory must be shot because I can never remember this phenomenon ever being an issue.

Are we are talking what I know as "woo boys" or maybe "washboards" or "corrugations" . . . a series of cyclic undulations similar to what can occur with a dozer grading heavy clay?

I honestly can't ever remember that being uncontrollable in the cut and in the fill I think it was mainly a function of speed when spreading nice material such as gravel.

To get an even spread we used to put the arm around both levers and force it out beneath the lip.

I would be really interested to see a picture of those skid pads still learn'n the phenomenon is obviously caused by material of which I have no knowledge.

Cheers.
 

still learn'n

Senior Member
Joined
Feb 6, 2012
Messages
455
Location
Kansas
IMG_0565.JPGIMG_0564.JPGIMG_0562.JPGIMG_0549.JPGHere is the only pictures I could find on my computer! These are the hydraulic ones and how they work is at the back of the floor of this finish scraper is the pivot of the skid pad and then it sticks behind the floor about 24" and the cylinder on the rod side is just plumbed into the main tube on the scraper for exhaust we don't need it for what we are doing the top one has a one way adjustable flow control valve and then is plumbed into a tank that can hold compressed air! Ok so how it works it the tank is half full or so of hyd oil and then compressed air on top so that when the scraper is lifted up the air pushes the hyd oil into the cylinder and extends it out, when the scraper is let down the flow control valve only lets so much oil back into the tank but is adjustable to be slower or faster depending on soil conditions or operators liking! So when the scraper wants to gouge in the pad will let it dig in but at a controlled rate not all at once. For example my understanding would be on duck walking if the scraper is going to fast tire pressure overcome the the bit pull down just a bit on whatever will give just a bit be it tire squat or whatever and then it pops it back out and does this at a fairly fast rate of speed side to side hence the term duck walking or wash boards! so then when the tires start squatting in this case the skid pad is more solid and only lets it dig at a more controlled rate and don't let it gouge! Not sure if you can understand that or not!
 

still learn'n

Senior Member
Joined
Feb 6, 2012
Messages
455
Location
Kansas
We use pull pans and so that's what ours were designed for! Havnt ever run a self propelled so don't know if it would work on them or not but don't know why not!
 

637slayer

Senior Member
Joined
Dec 22, 2007
Messages
486
Location
wyo
Occupation
scraper hand
i ran alot of b,c,d and e models and never had an issue with duck walking till the series 2 e. i dont know how they are balanced different or what but they naturally swing or rock side to side just driving in the lower gears, the g models are the worst, dont know about the elevating scrapers, given the added height i imagine could be worse. if your cutting edges are even and your back tires are even, dont give up hope, try to feel your back tires when your dumping, somehow they are getting uneven starting the duckwalk, if your in the same tracks of another scraper your doomed already. take a load lock the trany in second rap it way up dump your load about a foot deep, if you crowd your dirt out in one continuous motion it wont duckwalk.
 

JDOFMEMI

Senior Member
Joined
Jan 3, 2007
Messages
3,074
Location
SoCal
View attachment 124027View attachment 124026View attachment 124025View attachment 124024Here is the only pictures I could find on my computer! These are the hydraulic ones and how they work is at the back of the floor of this finish scraper is the pivot of the skid pad and then it sticks behind the floor about 24" and the cylinder on the rod side is just plumbed into the main tube on the scraper for exhaust we don't need it for what we are doing the top one has a one way adjustable flow control valve and then is plumbed into a tank that can hold compressed air! Ok so how it works it the tank is half full or so of hyd oil and then compressed air on top so that when the scraper is lifted up the air pushes the hyd oil into the cylinder and extends it out, when the scraper is let down the flow control valve only lets so much oil back into the tank but is adjustable to be slower or faster depending on soil conditions or operators liking! So when the scraper wants to gouge in the pad will let it dig in but at a controlled rate not all at once. For example my understanding would be on duck walking if the scraper is going to fast tire pressure overcome the the bit pull down just a bit on whatever will give just a bit be it tire squat or whatever and then it pops it back out and does this at a fairly fast rate of speed side to side hence the term duck walking or wash boards! so then when the tires start squatting in this case the skid pad is more solid and only lets it dig at a more controlled rate and don't let it gouge! Not sure if you can understand that or not!

From your description, it seems they are designed to work with the pull pans that lower the rear end in order to cut. I do not see this working on self propelled rigs since the rear is fixed, and they raise and lower at the front.

It does sound innovative on your type of pull pans though.
 

ShaneK

Well-Known Member
Joined
Dec 31, 2012
Messages
83
Location
Canada
From your description, it seems they are designed to work with the pull pans that lower the rear end in order to cut. I do not see this working on self propelled rigs since the rear is fixed, and they raise and lower at the front.

It does sound innovative on your type of pull pans though.

I've seen skid pads work successfully on pull pans that have a fixed rear as well.
I have never encountered them being used on a self propelled scraper, but I think it would be worth the effort in trying! Think of the productivity gained without duck-walking into the cut, and hitting it at a high speed...
 
Joined
Mar 25, 2010
Messages
19
Location
Louisiana
With Pull scrapers, duck walking typically happens in light cuts at higher speeds. Its the side to side rocking motion of the blade in the cut. This is often confused with power hop, with creates more of a washboard cut in similar conditions (usually light grade work). Slowing down a bit should cure it, but if speed is key, check your routers for wear. If they are new, add metal or drop to the lower position (on Deere scrapers). Tire pressures on both the tractor and pan can affect this too so make sure they are set at the manufacturers recommended pressures. Last, if all else fails, mounting fixed skid plates under the frog should fix it - no need to get fancy.
 

AustinM

Well-Known Member
Joined
Feb 16, 2011
Messages
68
Location
wyoming
just looking for feedback on what different factors cause duck walking and if anybody knows any good techniques to deal with it?



My opinion on what starts duckwalking:

when dumping is when one of the rear tires raises on the dumped material before the other and if the speed of the machine is constant, it puts the machine in a perpetual state of "wave" because of the weight of the machine that doesnt go away until both rear wheels are traveling on the same level at the same time for enough distance to get balanced.

when cutting, the opposite is true: it's when one side of the cutting edge hits the cut before the other or when the material you are cutting is softer or harder on one edge of the cut.

If I start duckwalking when I start dumping, I slow way down and lower the can so I'm half dumping, half grading. Of course you have to be very careful with the crowd so you're not putting too much pressure on the apron. If you're running by yourself (or without a motor grader cleaning up) and not worried about what's behind you for the other guys and i start duckwalking sometimes I'll just slow down a little and ride it out and let it duckwalk until I'm empty, then when I return to the fill with the next load I'll split the last one in half, keep the apron closed and lower the can and start grading at a slow speed (like 1st or 2nd gear and taking out the high spots) with the can until it's grading smooth then open the apron and crowd the material out really, really slow. On a side note, 9 times out of 10, I run with the cushion hitch ON in the fill. If I have to take out duckwalk tracks, I turn it OFF. I know it's supposed to be OFF in both the cut and the fill but that's how I roll.

If the machine starts to duckwalk almost immediately after you start cutting, slowing down and laying off the rear engine until it's cutting smooth again almost always helps. If it's near the end of the load before it's starts doing that, I'll just finish the load and split that cut in half the next time. So does lifting up and traveling forward until the rear wheels are past it and trying again. Just try a few different things until you find what works best for you.

stripping and placing topsoil is the worst because generally it loads and dumps in clumps so no matter what you do, you'll fight this phenomenon all day.
 

Terexisking

Member
Joined
Sep 9, 2014
Messages
12
Location
Colorado , USA
Shanek, #2 is covered by the router bits. Many times a scraper will duck walk easier when the router bits are worn out or new inserts have been welde in too high or at the incorrect angle. This makes it easier to penetrate the ground.
 

aog_allen

Member
Joined
Nov 10, 2015
Messages
19
Location
California
Occupation
farmer/earthmover
Duck walking with pull pans happen when your spreading material that's inconsistent or when out of material, then soon as your wheels hit a rock or a hole it cause the bit to lift up or dig in. We add metal floats that chain on ahead of the rear wheels and that helps with selfp propelled or pull pans. Our finish scraper has skids. Also keeping a lot of dirt in front of the bit helps.
 

Shimmy1

Senior Member
Joined
Aug 14, 2014
Messages
4,261
Location
North Dakota
I've spent over 6000 hrs running a pull pan. If you're having trouble with bounce, you need to go back to scraper school.
 
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