Awesome. I'm guessing the blades have pins and alignment holes? So you can set some angle or run 90 degrees?
Are both blades even with the ground when lowered to "grading" height? With the wheels it looks like the front blade would do most of the work the deeper you have it set to cut.
Yes, both blades have alignment holes and pins front and back to double the security of it if you hit something solid. There are two different degrees to each side you can set it to, or just set one angled and leave the other straight, etc..
The way it works is that you hook it to the tractor, and adjust the guide wheels height at the back to the rear blade is about a half inch off the ground. The height of the front blade is set by turning the top link turnbuckle on the 3 point hitch so that it's also about a half inch to an inch off the ground, depending on how rough of a surface you're starting with. Then basically drop the lift and ride, and it will make an idiot look like a pretty damn good grader in no time. In rougher ground I set the front blade higher and run over it a few times, then adjust the turnbuckle down a little to get it even finer.
Yes, the front blade does most of the work, when cutting heavy dirt or rock spills over the front blade and the rear blade since it's slightly off the ground disperses it. The front replaceable cutting edge wears out several times faster than the rear one.
The man who builds these things engineered the shit out of it, that center mount on top, if you stick a clevis in it to lift it, perfectly balanced. We discovered these things 15 years ago or so, while doing work with a landscaper. he had one and we asked about it, he took off in one pass across a lot we'd just ripped stumps from and it was unlevel as shit, did a couple loops over it all and it was basically done, so we bought one. Now we have 3 of them, one for each different sized tractor we use.
Griffin Manufacturing Company in Suffolk, Virginia builds them.
The one in this picture has the extra tabs welded lower for our quick hitch system on that tractor. He's never set them up to run with quick hitches, he wasn't sure it would work, but we welded those tabs on and it works just like it's supposed to, just adjust the top link as i said.