I’m not quite clear of you’re using a box blade or back blade or land plane. If using a box blade or back blade, adjust the top link to dig in just enough to pick up some material but not much. The washboard will make the tractor bounce so you’ll never get the washboard out unless you have the blade floating in the full down position, which is why you have to control the cut with the angle using the toplink.
Once you have it set right, run back over it and do NOT go slow. Running around 4 to 5 mph should start to take the washboard out. You may have to run over it several times to get all of the washboard out.
If using a land plane, I have no experience with those so although I think that should cut out washboard by just running over it, I would defer to others who have land planes.
BTW you certainly can fix a dirt/gravel road with a box scrape and/or back blade. This one is about 1/2 mile private road plus a couple of short driveways. Started out W shaped with water running down the wheel tracks instead of the silted ditches. Put in 30 years before and not touched since. Reshaped the roadbed to put the crown back on it, cleaned out ditches and turnouts, topped with 3/4” rock (about 150 tons).
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This was after ripping with the boxblade and resetting the crown. Roughed in with boxblade and did a bit of touch up with the backblade before topping with fresh 3/4”.
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Finished result. No more W. No more washboard.
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Used the loader. Some wasn’t dump truck accessible for tailgate spread due to trees being to tight for the quarry’s quad axle dump trucks, so there was a good bit of spreading from piles with the loader.
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72” light duty backblade. It’s a manually adjustable backblade and it works. That’s the only good thing I can say about it. It’s quite old and as basic as they come.
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Boxblade is also 72” and nothing fancy but heavy enough to do some actual grading.
So, yes I’m sure it would have been an easier and quicker job with a crawler with a gravel box and a true road grader, which is why DOT doesn’t use small tractors to maintain hundreds of miles of gravel roads, but a couple days with the tractor and blades did the same thing. May take a bit of experimenting and practice but if someone thinks it can’t be done with a CUT and blade that’s more a comment on the operator than the equipment.
