Grading--what am I doing to cause this?

[mechtheist]

The amount of input to this thread indicates one of the primary uses of compact tractors. I suspect that mowing and/or "bushhogging" would be at the top of the list but roadway maintenance would be very close to the top.

Yeah, I am surprised at the number of posts. All very useful and consistent info. Thanks all, it's going to help a lot.

 

[nickfank]

Regarding the "gravitational anomalies" in your drive, note that if there are any areas where it goes up or down hill, even slightly, then the geometry changes.

When the front wheels go uphill a bit, now the blade hanging off the back is lowered relative to the center. Worse, the lowered blade digs out a little low spot so that next time you pass over that area, the effect is greater.

Going downhill, even slightly, lifts the blade, and again the effect adds up on every pass.

Since my own drive goes over hill and dale, I've often wished I had a way to belly mount a blade equidistant between the wheels so I'd have something like a road grader.

 

[Djwshady]

Yup, we call this "chatter." Just need more weight.

 

[funnyfarmdh]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
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[3 Horse Ranch]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
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If that were my driveway, I would be hooking up my drag harrow with the tines up and run up and down the driveway a few times to smooth it. Otherwise, it looks pretty good for the kind of material you have to work with. It looks similar to what I have which is 4" to dust. It's good road base, but lousy top coat. Some 3/4 minus would make a smooth finish, but the cost can add up quickly.

 

[funnyfarmdh]

I have found specially with box scraper that any irregularities in the exeisting grade will translate into ups and downs of scraper as the wheels go over the high and lows. I try to start from a flat area then grade backwards so the wheels remain on a level surface. You could also use a drag such as a railroad tie with chain link fencing trailing to take out some of the irregularities

 

[mechtheist]

If that were my driveway, I would be hooking up my drag harrow with the tines up and run up and down the driveway a few times to smooth it. Otherwise, it looks pretty good for the kind of material you have to work with. It looks similar to what I have which is 4" to dust. It's good road base, but lousy top coat. Some 3/4 minus would make a smooth finish, but the cost can add up quickly.

Don't have a harrow, I could do it in drag and that would be a pretty harrowing experience,would that do? Had to look up '3/4 minus', thought it was a typo, that would be great but I don't want to spend any money on this, it's good enough for for me. What do you mean by '4" to dust'? Can't figure that out. Where I'm at it's all limestone with a little soil or weathered limestone between the rocks, if there is a between. There can be large slabs in places or just lots of smallish rocks mixed with bigger to a lot bigger. Fortunately, where the road is is mostly the smallish.

 

[gckshea]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
View attachment 725180

Number one thing I have learned is SLOW DOWN your forward speed. Box blades and straight grader/scrapers are about going slow and giving yourself time to feather the three point lift arms. Not every grading job is about dropping the blade and dropping the clutch - it's very much an active event. Weight on the grader blade and box blade will help in rocky terrain, but speed, or lack of it, is very key to a good first few passes. If you establish ripples and undulations early, later passes seem to make them even more pronounced...unless you fix it by slowing down and feathering the draft lift handle on the tractor.

 

[MossyDell]

I'm afraid it's going to have to be the box blade

Yes! And though the underlying washboard issue may have been caused by too little weight, I agree with those that say rippers set shallow are the cure.

No reason to rip deep and turn up problems. Shallow scarifiers will take out that ripple.

I saw my father frustrated by this problem decades ago. He had a 2WD Kubota 13 hp B6100 and a box blade of 36" or 40". But this was on central Florida sand and it didn't come with scarifiers. It was not heavy, and though he had loaded tires his tractor was light too. His driveway was sand and packed shells. The light box blade skipped along, digging in and popping up. Probably not many then and there used scarifiers so he didn't think of them as his cure.

I wish I knew anything about this issue then.

 

[MossyDell]

Angle the blade harder by bringing the left side farther forward.

I guess being able to angle like that is a blade's advantage over a box blade. I can just tilt my box front to back and side to side of course.

 

[Paul40]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
View attachment 725180

 

[Paul40]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
View attachment 725180

 

[Paul40]

The two grader operators do a terrific job keeping all of the gravel roads in our RM in good shape. They do the road in 3 sweeps - once down one side to get the gravel to the centre, then the other side on the return sweep, winding up with a pile of gravel in the centre of the road. The final sweep is down the centre of the road, so the road is close to level in the centre, but lower on the edges.
While I don't particularly like driving on the road just after it's been done, because it's like driving on marbles, with a bit of traffic, which is sparse around here, two smooth tracks develop, and it becomes almost like driving on pavement, but there are a couple of places where I normally drive where there's always been the "washboard" road you describe.
I'm not sure why it's only, and pretty much always, in the same spots. I don't think it has all that much to do with the weight. Not only is the blade itself very heavy, but it's solidly attached to a very heavy grader, not floating, like my snow blade. Other than the final sweep, which is only for spreading the gravel, instead of scraping the road, the blade is always angled.
I realize that I'm not providing you with a solution here, more like an explanation. Maybe the road bed itself is different in those spots, and yours may have a similar problem.

 

[mechtheist]

The two grader operators do a terrific job keeping all of the gravel roads in our RM in good shape. They do the road in 3 sweeps - once down one side to get the gravel to the centre, then the other side on the return sweep, winding up with a pile of gravel in the centre of the road. The final sweep is down the centre of the road, so the road is close to level in the centre, but lower on the edges.
While I don't particularly like driving on the road just after it's been done, because it's like driving on marbles, with a bit of traffic, which is sparse around here, two smooth tracks develop, and it becomes almost like driving on pavement, but there are a couple of places where I normally drive where there's always been the "washboard" road you describe.
I'm not sure why it's only, and pretty much always, in the same spots. I don't think it has all that much to do with the weight. Not only is the blade itself very heavy, but it's solidly attached to a very heavy grader, not floating, like my snow blade. Other than the final sweep, which is only for spreading the gravel, instead of scraping the road, the blade is always angled.
I realize that I'm not providing you with a solution here, more like an explanation. Maybe the road bed itself is different in those spots, and yours may have a similar problem.

I think the rippling is only going to happen when the road is pretty hard, softer ground would not support the kind of forces needed to move the blade fast enough, at least that's my poorly-informed thinking.

 

[DSteiner]

I don't have a lot of experience doing this basic task. See the photo, I've used both a blade and box blade and keep getting these ripples and have no clue why. I've tried it with the lift arm float mechanism in and out and the slow-return lift adjustment loose and nearly off and nothing gets rid of the ripple. The tractor is a Branson 3520 and it doesn't have draft control, not sure if that would help. I'm in cenral Texas hill country, v hard ground, very rocky, I usually try to do any grading when the road is just a bit wet. Anyone have any ideas? Is it something obvious and I'm just too much a noob? Thanks for any suggestions.
View attachment 725180

I see several problems. 1: tractor only has position control. Front wheels go over a ripple the blade mounted behind the rear wheels go down. Then back wheels hit the ripple and come up causing the blade to exaggerate and go even higher. 2: blade too light 3:blade behind the back axle exaggerates tractor movements.
I had added draft control to my Ford 1320 which helped but not enough. I added a gauge wheel out back so tractor rear axle went over ripples etc the blade only moves up half the distance. Someone mentioned 100lbs per foot of blade width. IMO that is not enough but would depend on soil being graded. For my soil at least 200lbs per ft or down pressure on the 3pt hitch which I don’t have. Using rippers may help. I don’t know.

 

[Gord Baker]

Add a lot of weight, slow down, put blade parallel with rear axle, don't go fast. You must 'cut' the ripples and valleys off. Scarify if possible several times.

 

[Fladogman]

I've never tried the blade backwards, others have mentioned it and it's a simple obvious thing I should have thought of. Turning the blade around I have done but for going backwards. 'Floating', does that mean you have a hydraulic top link in float?

Edit--your link isn' working for me, says I don't have permission. Would pretty please help?

Yes I have a hydraulic top link but what I mean is by turning the blade backwards it floats over the ground and will not cut in. I can't get the link to work either. It was a picture of my blade, not important

 

[Fladogman]

You can float a box blade too by extending the top link out.

 

[Henry007]

What MPH are you utilizing for grading? My guess is too fast.

Yes Tx Jim is correct. To much speed.

 

[ovrszd]

The two grader operators do a terrific job keeping all of the gravel roads in our RM in good shape. They do the road in 3 sweeps - once down one side to get the gravel to the centre, then the other side on the return sweep, winding up with a pile of gravel in the centre of the road. The final sweep is down the centre of the road, so the road is close to level in the centre, but lower on the edges.
While I don't particularly like driving on the road just after it's been done, because it's like driving on marbles, with a bit of traffic, which is sparse around here, two smooth tracks develop, and it becomes almost like driving on pavement, but there are a couple of places where I normally drive where there's always been the "washboard" road you describe.
I'm not sure why it's only, and pretty much always, in the same spots. I don't think it has all that much to do with the weight. Not only is the blade itself very heavy, but it's solidly attached to a very heavy grader, not floating, like my snow blade. Other than the final sweep, which is only for spreading the gravel, instead of scraping the road, the blade is always angled.
I realize that I'm not providing you with a solution here, more like an explanation. Maybe the road bed itself is different in those spots, and yours may have a similar problem.

Washboard is usually at intersections where traffic speed changes dramatically and/or on steep inclines where wheel slippage gets them started.

The OP's problem is blade chatter.

Interesting to read all the posts and theories. All must be taken with a grain of salt. My roadbed type isn't like the OP's or like most of the posters. We should always consider that. What works for me might not work for the OP.

I've maintained 16,000 miles of gravel roads in NW Missouri over the past 32 years. But I don't know how to maintain his Texas road. I know theories and can offer suggestions that would work for me.

My first is to do the maintenance when the roadbed is damp. In the pic the roadbed is wayyyy too dry.

Interesting discussion though.