Designing a LPGS

[aeblank]

So, I really want a LPGS (Land Plane, Grader, a million other names that makes it hard to find on CraigsList).

I'll probably buy one (Land Pride or Grademaster), but thought I'd design one up just for fun.
I'm an engineer, so I figured I'd model it up and make a drawing and send it to a fabricator I know. If it comes in at sub-$1000, I might just go that way.

All that said, I don't have structural steel experience. I could figure out how strong it needs to be, pick the right thickness/size tubing, etc. etc. But....... I don't want to put that much time in it. So I figured that I'd post here. In return, I'll probably post my drawing(s) for others to take to their fab shops or build themselves.

I intend to make it adjustable like the Land Pride, but otherwise built like a Grademaster (or sort of Befco). No scarfiers. This ebay post has nice pictures (Brand New Befco 72" 3 Point Hitch Road Grader Blade | eBay).

I don't want a 2,000lb unit. People can adjust thickness/sizes to their own liking if they want. It will be a simple design too, for cost. I'm looking at a 72" unit at about 1,000#, I'd imagine. Perhaps with provisions for an add-on 55-gal drum of water for weight or something like that.

So, I need measurements.
How thick are the sides? How long are the skids? How thick are the skid shoes? What is the angle of the blades and what size angle iron is it, what is the size (and thickness!) of the cross tubing? What are the measurements of the 3-pt hookup (must be quick attach!)? Hole diameters, etc. What is a good blade source, or help me spec. a logically hard enough raw material.

I can stab at most everything and get close. But it'd be just like me to pick a randomly impossible to source tubing that doubles the price. I'm hoping by doing this post/getting feedback I can avoid all that. Heck, what grade of steel should I even call out? I'd likely leave it to my fabber, but if I can know I'm spec'ing something logical, then I will.


So, have at it, if you're interested.

 

[CNC Dan]

you might want to see if you can get used road grader blades, then build arround that.

Abrasion resistant steel is called AR500. Good for earth contact.
Or you could add hardfacing to mild steel (A36/1018),where it contacts the ground.

 

[aeblank]

Thanks for the reply.
This is what I have, with very few real dimensions.
No slots/fasteners yet for the adjustable blades. Heck, no blades on there yet either.
Probably 1/2 hour of actual work.

Trying to make pieces the same if I can. All the tabs are the same, the 3-rd point upright and the center horizontal support are the same. Left/right sides will be the same (except for the band welded around will be left and right justified to make the sides).

Hopefully this screen capture posts right..

 

[bcp]

Land Pride specifications and measurements through the links below:

GS15 Series Grading Scrapers | Land Pride

GS25 Series Grading Scrapers | Land Pride

Hitch specifications:



Bruce

 

[Oliver1655]

For the skids, I used 12" channel iron the cut an angle on the front end using 3/8" x 3" flat to finish it off. The gaps work great for hooking a chain to.Just reach through the gap & hook onto the 3/8" flat & you are done. I like pulling with a chain versus using the 3 pt hitch for making tighter turns. On mine I also welded on sockets to where I can mount it on the loader forks. Better control since the front tires pivot than on the 3 pt if working in smaller tight areas. For long runs with where you can pick it up on the ends, then the 3 pt is the way to go.

I used 3/4" x 8" x 4" angle iron. for the cutting blade supports. I wanted weight without having to add bricks or a barrel of weight. I like the visibility & have read several comments from other members about how the weight "box" interrupted the flow of the material. Mine is 6.5 ft long and has 8' wide cutting edges. I have found having the cutting edge level with the bottom of the skids works well in most cases. Jenkins' land plane has it's blades fixed this way & he seems very happy with it.

My build thread: http://www.tractorbynet.com/forums/build-yourself/316089-land-plane-yet-another-build.html

 

[aeblank]

@CNC Dan - Thanks. I'll likely just call out the AR500.
@bcp - Thanks also. Measurements integrated into layout. I don't tend to believe the pin diameters, so I'll be measuring mine. I thought they were 7/8".
@Oliver1655 - Thanks also also. I did catch your thread already. I didn't read every post, but I certainly looked at all the pictures. I may put the option of the C-channel on my dwg. I can see where depending on what "scraps" one can find, it can be significantly cheaper. That said, I have no idea what might be available, so a conversation with the fabber seems logical. 3/4 x 8 x 4 angle? Dang. Off to beef mine up.

I was hoping for some more structure measurements. At this point, all I need to do is throw a blade on there, and the design is "done"... Except do my tube, angle, plate sizes/etc. make sense. Once I assign a material, I'll have some idea based on the overall weight, but I was hoping for more..

Anybody?

 

[GPintheMitten]

I think you need to add side support to your top link attachment.

 

[jenkinsph]

The measurements bcp posted are correct for the quick hitch couplers as they use cat 3 sized pins. You can use the cat 1 pins and add bushings. Also note in the top left of the drawing the hitch pins are all aligned plumb where yours has the top link set back, this should be changed.

Your skids look nice but it is a good idea to make them work well in both forward and reverse travel. For the blade mounting I would use 6"x6"x3/4" angle iron to have some weight but 4"x4"x1/2" is the minimum. Make sure you have as much room as possible between the blades and the upper cross members, mine are closer than they should be and can clog up with damp soil.

 

[aeblank]

"nobody" else has side supports on their top links, but I think I'll add some small gussets there and between the beams/skids.
Cat-3 pins makes sense. I'll put in the 7/8" pins and use bushings, since a quick-hitch shouldn't be a requirement.
I did see the mounts were plumb. I already changed that, but I haven't posted another picture.
I've pondered putting a SSQA plate on the back of it. We'll see.

 

[aeblank]

960lbs as it stands. I'm in the right neck of the woods.
Would love some beam size confirmations.
6"x6"x3/4" angle for the blade supports, as suggested.

3/8" side walls?
3/8" skid shoes/wraparound?
4x4x.1875 front beam?
2x3x.1875 mid/rear beam?
3/8" pin tabs?
1/4" gussets?
1/4" plate to hold the angle, held in by up to 6ea 3/8" bolts?
3x3x.1875 upright for 3-pt and middle support.
blades at 5 degree angle?
blades 15" apart?
blades in front 2/3 of skids?
What do do about the blades where the meet the skids (at an angle). Probably leave them square cut and whatever gap is ok....?

I'm confident it's build-able and would work. But anything to hedge my bets against bending/breaking/etc. is good to do now.