The blade face on my D6 is worn very thin and I've repaired it in several places so I think it's due for a re-skin. When you do it, do you cut all the old skin off? I'm thinking I probably need to since there wouldn't be much weld to on the old. Someone has added a heavy push plate in the center, which will have to come off anyway, and the angled end sections have also been plated over. What kind of material should I use and how thick? Something like 5/16"? There is a local shop that builds tank trailers and they have a large plate roller. Not sure if that's the best way, or if I should find someone that could "bump bend" a sheet on a brake press. With a plate roller I'd think you would have to make it extra wide since I don't think it will roll a curve completely the the edge of a plate.
The ones I have been around have left the original skin as support. AR400 was used. A cardboard template was used for the radius. Tell them the width and height let them tell you how much oversize it will need to be.
Even after having the plate rolled you will have to dog the cover plate as tight to the original skin as possible. The thickness of the plate always depended on my customer's projected life of the machine tolerance for paying for the plate. Most never wanted to pay of AR400 so I used 3/16 T1 and hard faced the bottom of the edge.
Our D6C had the moldboard relined before I bought it & it is at least 3/8" thick & whoever did it, made a nice job of it. AR400 will give you better wear but if your are not putting a lot of hours on the machine, mostly doing your brush clearing etc. on your farm, mild steel will be fine provided the environment is not real abrasive. I would stick with at least 3/8" if you can see your way clear to do it. I can check the hardness on ours & get back to you, to determine if it is mild steel or not. Note on ours they put 3 plates on across the flat part. I do not think it will be necessary to remove the old skin, just dog it down as tight as you can before welding as suggested by others. After we bought the machine we did some repair work on the little triangle areas & the angled pieces near the outside edge, beyond the of the flat part where the 3 rolled plates are, as some of that had worn through. We also added some new 3/4" plates up the outside edges of the blade when we did the other repair work. If you can plug weld a few spots in the middle of the rolled plates that would be good. Perhaps you could post a couple of pictures of your moldboard?
Thanks for the replies.....I'm not sure if my use warrants buying AR400 but T1 might be an option. I have a steel supplier that can get just about anything so I'll check prices. By the time I torch out the push plate in the middle there may not be much left of the original skin. (unless I patch around it) I think the plate is 3/4" so it will take a bit of work to remove. Towards the bottom it's so thin I had trouble welding patches over it without burning holes through the skin. The angled ends have been plated so I don't think I'll have to do anything there.....They used at least 1/2" thick plate on them. I wonder what the original thickness was on the skin?
As I remember on the old machines I worked, the side boards were 3/8" and the mold boards 5/16" nominal. Push pates were added to keep from pushing thru thin skins designed for dirt pushing not other machines or stone. Cutting edge support was usually 1/2-1" thick and either false floor with braces to the mold board or just back braced.
Check with Cat. My old "One Safe Source" catalog shows re-skin part number 2J8526 (5-pieces) for the D6 straight blade. Material is 3/8" thick, doesn't say what type.
I just checked & on my D6C blade, the reline plate which was done before we got the machine is 1/2" mild steel. It still looks to be in real good shape yet. All we did was add the little triangle wedges on the bottom face of the blade & rebuilt up about 1/2 way on the crescent plates both ends where the bottom portion had wore through.
Googled that part no. and got a cat price of $849.50 ea. Weighs 129 lbs so I'm guessing it takes more than one.....hopefully not five at that price.
I have used a carbon arc in the past to take out the thin stuff at the bottom up about six inches. The problem with that is usually there are vertical or horizontal frames that the skin is welded to from the back side. I laid plate or bar stock in place of what I cut out and the put the wear plate on top of that. The corners where the corner bits bolted into was the other big problem. Saddle jockeys would wear the corners all the way into the bottom bolt holes and then it was a mess to cut that piece out and put new part back in a way that lined all up with the rest of the edge again.
When installing a new skin it can be a bear to pull it tight to the blade. One way to pull it tight to the blade is to weld 1/2" by 2" or so steel bar stock sticking out from the original blade. Cut a slot in them. Cut slots in the new skin to fit over the bar stock and drive steel wedges into the slot to pull the skin back tight. After welding your plug welds in the field cut the bars off and weld them up solid. Good Luck.
OIH at work they roll then slightly smaller radius. Then weld the bottom, plug weld the middle then push the top tight with another dozer and weld that.
I 2nd this approach. Much easier to roll the radius a little tight & have pull that last end down than to have a gap in the middle to deal with.
Sounds like a good way to go especially if you have a push machine at your disposal. I must be showing my age again, fixing with out the "proper" accessories.
I'd thought about making the radius a little big too......and welding the bottom, then using chains around the blade and jacks to push the center down. Not sure if I'll try to do it on the machine or pull the blade loose from the push arms and bring just that into the shop. At any rate, I've got a couple of other projects to get out of the way before I can get to it.
Leave the 3/4 push plate and add material all around it ?
Yair . . . . Seconded.
Works for me!
Probably the best idea.....much less work.
There used to be a place in Atoka OK called Diamond Manufacturing that that sold the skins already rolled. We put a couple on several years back and they were not too hard to do. Not sure if they still sell them but they are still in business. James