Rookie questions

[Hitachi EX3500]

Hey all!! I am not gonna try and pretend that I am a grader guy, but have been around one enough to be dangerous on one. A lil background, I grew up with my family owning/operating a small excavating business. Due to matters that don't need to be discussed here, I never learned the intricacies of operating a grader. I now work in a coal mine and primarily run a shovel. On occasion I will work extra and get put on a grader for a shift ( decrepit old 16's not sure of the model).

Here's my question. What is the general purpose of rolling the mold board over? In our general application, I see no purpose in it. I feel like it exposes to much of the cutting edge to the ground and takes away it's cutting capability. I feel like, in our general purpose, our roads need cut. And in order to do that the mold board needs to be standing as upright as possible, angled all the way around by the tire and cut it all the way across the road, then bring it back across. But that's just my thoughts. Our usual grader guy retired Friday and they put a guy on his grader. When he came on the dirt bench behind me he had the board rolled as far over as it would go, just shy of 90* to the machine, tires practically smoking, and doing next to nothing.

Another reason I ask this question...... Long story short, another person was gonna train up on one, looked in the cab and promptly and thoroughly got intimidated by the line of levers in it. Now keep in mind this is someone that has never been in one!!!! I made the comment that you really only need 4 of them to do what needs done at our place..... I was informed that I was wrong ....you have to roll that "blade" over.

So give me your ideas and opinions and correct me if I'm wrong cause it drives me slap insane to watch someone beat the crap out of a machine.

 

[teamlayton]

Hi I worked up in the oil sands on grader.On the haul roads all your doing is moving the windrow across the road and back making a smooth surface for haul trucks. In the oil patch it was all about speed get over the roads fast.With the blade rolled forward you are pushing down and can run fast with out bouncing.With the blade rolled back you will flip rocks out and start cutting to deep(start making soft spots).Up there we were working with mostly sand and clay capped roads.If it rained I would roll back the blade and cut just the top wet part off so the trucks would keep running.When it stated to dry out I would work with my blade rolled forward spreading the wet clay thin so it would pack.I would try different things and see what works best on the road surface you are working with. The truck drivers will give you feed back if they don't say anything its all good.

 

[Hitachi EX3500]

Our roads are all built out of rock. We are running 789B's and R190's so the roads take a pretty good beating. My thoughts are that you would want to cut some to carry across to fill any bad places in the road.

 

[grandpa]

A couple reason's for rolling the moldboard down, is 1). the material moves across at a slower rate 2) It allow's for more circular motion in your material allowing for the fine's to be mixed more even with the coarser materials, 3) The downward force (as mentioned by Teamlayton) aids somewhat in compaction.

 

[Hitachi EX3500]

Normally our roads have the appearance of a asphalt road. They are compacted way beyond anything that a grader could add to. I understand that with the blade rolled over it's not going to cut as much and at times it may be called for. But would one approach a haul road that is compacted to heck and beyond with your blade rolled over? Or would you get it up on its edge and try and cut it? Pulling big rocks up really isn't a factor due to the fact that our blasting department either makes shelled corn out of it or it's so big it takes 2 D-11's to move it. I'm just trying to get a grasp on things. The only time I ever saw anyone else run with the blade turned all the way over like that was to lose a windrow

 

[grandpa]

Well on the first pass, I'd have it rolled up enough to get a good even windrow cut up and established ( unless your company doesn't allow you to have a windrow)?. Once I got my windrow established, then I'd roll the edge over and continue moving the windrow on across the roadway. Its just they way I'd do it.

When grading with your edge rolled over, it sharpen's you edge so when you roll it back into cut mode, it cuts real nice for you.

 

[Nige]

If the road surface is as hard as you say then you may have to think about dropping the ripper into it first to give it a stir up before grading, especially if it doesn't have large rocks in it.

 

[AKSNOW]

Just wanted to add a couple of thoughts. First of all never run the blade all the way up or straight it will shock and damage the unit. I was thought to start with top blade tip forward 4-6" for the first cut and roll forward 4-6" every cut after and finish rolled over to compact,mix fines,and eliminate duck walking.15 + years in grader and still loving what you can do with one!

 

[keerym]

From the Caterpillar Application Guide for Motor Graders.........

Moldboard tip. This is a very important feature: its proper use will increase machine productivity, increase cutting edge life and could prevent machine damage.

The top of moldboard can be tipped ahead of or behind the cutting edge. This helps position the cutting edge at its proper angle to obtainthe desired material cutting and rolling action. Maintaining a rolling action on the material while working will reduce horsepower required and provide maximum productivity.

Normally start with the moldboard top positioned approximately 2 inches (5 centimeters) ahead of the cutting edge. From this position, tip the moldboard forward or back to obtain and maintain the desired cutting-rolling action. Tipping the moldboard forward will increase moldboard throat clearance (distance between the top of the moldboard and the bottom of the circle). Generally, a wider throat opening allows better material flow along the moldboard in all soil types. Material buildup into the circle area may increase circle wear. It can also stop material rolling action and cause it to be bulldozed. Bulldozing material requires more horsepower, more traction, and reduces motor grader productivity.

To cut hard material or for finishing work, tip the moldboard further forward than the start position. When finishing, tip the moldboard top 4 to 5 inches (10.2 to 12.7 centimeters) ahead of the cutting edge so the cutting edge is approximately 90 degrees to the cut surface. This moldboard tip position will generally position the drawbar parallel to the finished grade. When the drawbar is parallel to the finished grade, circling the moldboard will have little effect on the cross slope being cut. The amount of tip required will change slightly depending on the machine, tire size, cutting edge size (6 or 8 inch [15.2 or 20.3 centimeters]) and if cutting edges are new or worn.

Tipping the moldboard forward or back will change cut depth or blade height off the ground across the entire moldboard length. The tip control, for example, can be used to raise both ends of the moldboard for feathering material at the end of a cutting pass or for increasing cut depth over the entire moldboard length by use of a single control. Cutting high bank slopes or deep ditches requires more forward tip on the moldboard to obtain the proper cutting-edge-to-material contact. Attempting to cut with the moldboard in the full rear position in these applications, or with worn cutting edges, could result in difficulty penetrating and cutting the material.

N O T E
Use caution when working with the moldboard at full back tilt. Damage can occur to the moldboard tip pivots, cutting edge attachment bolts and support area for the cutting edge. This may cause a reduction in cutting edge support.

For maximum cutting edge life in road maintenance work, maintain a near constant tip angle. Frequent changes to tip position in this application result in accelerated cutting edge wear. In general, tip the moldboard rearward for heavy clays and cutting packed snow or thick ice, after first penetrating the material with the moldboard tipped forward. In snow removal work, tip the moldboard so the cutting edges are approximately 90 degrees to the work surface. This allows the moldboard to slide
over the road surface with less damage TO THE ROAD and over many obstructions without damage to the machine.

 

[Hitachi EX3500]

Thanks for the input guys!!! I can understand running with some tip in the moldboard. But what I am saying is theses guys are running with it rolled as far over as it can possibly go.

 

[Nige]

Thanks for the input guys!!! I can understand running with some tip in the moldboard. But what I am saying is theses guys are running with it rolled as far over as it can possibly go.

That would appear to be the lazy man's way of doing it from what I've seen.

 

[terrasmooth]

Thanks for the input guys!!! I can understand running with some tip in the moldboard. But what I am saying is theses guys are running with it rolled as far over as it can possibly go.

When you have the moldboard rolled all the way over; it is just scraping the material. Any material accumulated in front will create a serious drag as you are pushing it into the grade in front of you. The only time I would ever do this is when I get down to the very last passes on a finish job.

I find that running the moldboard tipped approximately 20-30 degrees forward is a good all around position.
When I have a large amount of material to move, I want the moldboard rolled back to get the maximum ‘rolling' of material across the face of the board (less resistance)… angle of the moldboard perpendicular to the frame of the grader has a lot to do with stability, material handling and control also.

 

[RZucker]

That would appear to be the lazy man's way of doing it from what I've seen.

Yep, that just makes for a very expensive box scraper in my opinion. Especially maintaining roads. The whole idea I believe is to CUT the problems out, not cover them?But I myself havent been on a grader for 15 years so I cant poke at people.

 

[Hitachi EX3500]

I tend to agree with all that you guys have said. I don't feel like they are doing things properly, but I don't have enough experience to know for sure who's right and who's wrong. I guess I will keep my mouth shut about the issue at work, and run it how I see fit on the rare occasion that I do run one. Thanks again for everyone's input

 

[Nige]

I tend to agree with all that you guys have said. I don't feel like they are doing things properly, but I don't have enough experience to know for sure who's right and who's wrong. I guess I will keep my mouth shut about the issue at work, and run it how I see fit on the rare occasion that I do run one. Thanks again for everyone's input

When you do get chance to run one and if the road surface is hard, try what I suggested above and run the ripper through it a few times to give you some loose material to work with. Often what I've seen/had explained to me is the reason for rolling the moldboard right over forwards is that the material is so hard it won't cut with the moldboard in the correct position. This is typical of many mine road if they've had loaded haul trucks run over them, they can be like concrete. Solution - loosen the material with the ripper before you try grading it.

 

[rsherril]

My issue with using the rippers is you can haul up some undesirable material like pit run cobbles. I would suggest a test section that can be easily cleaned without leaving undesirable material where the blade will pick it up again. I carry a potato fork for such conditions so I can easily pitch the offending material far off to the side. Rock rakes are the preferred method but not in my budget.

 

[Nige]

To me that's the whole idea. If you root something up that's too big then it has to be bladed off to the side of the windrow and you're left with more workable material for all the future times the road is graded. Especially if the climate tends towards freezing temperatures in winter the road will tend to "grow" rocks just like farmers' fields do. The rocks push up from below with the action of the frost and have to be got rid of somehow.