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Thread: 98 Jeep ZJ "SHTFV"

  1. #51
    Join Date
    Feb 2011
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    Default Bumper Design Phase

    The next step was to figure out how to attach the bumper to the uni-body. This is the part that I riddled with last time I did one of these. It just blows my mind to attach a winch bumper to a unitized chassis. A frame would offer a tremendous amount of confidence. In this case, I have to remember that I did it before, and even used to the winch to dead pull it out of the mud in a river up to the middle of the doors, so I am going to go the same route. The first step was to get access to the holes in the side of the chassis' boxed "frame rails". In order to to this I need to make room for a plate to slide inside the holes. The holes start out as ovals, and I need them to be rectangles, so out comes the die grinder again..

    First mark the approx. locations of the cuts



    Then get after it with a die grinder and try to make decent straight cuts



    Then I just pull out the pieces



    The result gives me straight out access to the inside of the boxed material



    Now that I am to this point...



    I decided to pull out the winch and mock it up for position. The location and height of the winch determines the limit to approach angle. I see a lot of bumpers where the winch sits up on top of the bumper, and that just adds to the leverage of the brackets attached to the weak sauce chassis, so I decide to split the difference and will try to mount it just about here


  2. #52
    Join Date
    Feb 2011
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    Default Bumper Design Phase

    This is the "fun" part for me, it is where I get to be creative and make some mock up pieces to see how the bumper is going to look. Eventually I will use .188 cold roll mild steel to construct the bumper, so I found a material similar in thickness to use to represent the steel for design purposes. I went to the local "Joann Fabric" store and purchased 8 sheets of foam core poster board. This should work perfect...



    I started out by building the bumper brackets that go inside the chassis



    This will bring .188 material to the front of the chassis, the next piece to make will represent the profile of the center of the blade to include the top surface, front face and lower slope. To be honest, this is kind of a guess



    Due to the fact that these patterns will eventually be used to cut the actual parts from, I want them to be as straight and accurate as possible. For that reason I elect to use my stomp shear to cut most of the straight edges, at least where ever possible



    Here is the finished bracket



    I then use my temporary welder (Blue painters tape) to attach the bracket in its intended location. I also decided to run a plate across the front face of the chassis in between bolt in brackets, as pictured here



    I place the bracket on the other side, and then make the front face. This will result in a box shape that I can slip the winch in to confirm fitment



    Here is the side profile, and also the time to make any final decisions on the shape of the bumper. From here on out, all plates will attach to these and be tied to these angles



    The lower slope plate is next on the list, it also helps to square up the box, and keep it square as I move on to the next plates


  3. #53
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    Feb 2011
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    Default Bumper Design Phase

    This is where my project differs significantly from my old ZJ project. I had a 1993 with a straight across grill. This 98' grill dips down in the center, and throws a bit of a wrench in my design phase. I decided to just start making plates and see how it looked

    Here are the top filler plates that go up to the edged of the grill



    I decided to just make the plates angled for simplicity instead of trying to get crazy with some radius action , I guess that is because I couldnt figure out how to radius actual .188 steel plate



    Next I made some outside plates to mock up and figure out the inside dimension of the turn - around the headlamps



    Once I had the inside dimensions sorted out, I made some oversided plates so that I can draw in the final outside profile



    I spent a little time riddling with the shape of the bumper on the side of the vehicle, I finally decided to oversize it and make sure it would mat up half way decent with the flares in intend to install in the future



    It looks like it is too wide, but it leaves me enough room to drop a tube on the corner and protect the headlamps from branches and brush



    I had to trim the lines and see how it was going to look



    It seems to look wide here, but my camera has a crazy wide angle effect



    The next plate to add was the front side faces. I just figured what height I wanted on the outside, traced the profile of the top and cut it to fit with a razor blade



    It is starting to look like a bumper!!



    The kick up on the grill is really starting to grow on me, it adds character!!



    I only had the lower slope side plates, the far side plates and the rear caps (which will be done sans a pattern for now) left to do
    The lower slope side plates are fairly easy, just connect the points



    It looks like it will work, the side plates help!




  4. #54
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    Default Bumper Design Phase

    The final front bumper design seems to be very close to what I was looking for. I will have to take a plasma cutter to some sheet metal under the front bumper, but I am not too worried about it! This camera makes it look way wider than it is, kind of bothers me in pictures, but suits me just fine in person I may clip the corners at a 45 degree angle just to get rid of some points, but I have not decided yet. I can always take a plasma to that too after it's done if need be!!








  5. #55
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    Feb 2011
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    Default Bumper Design Phase

    Next up, rear bumper design to include spare tire carrier and Jerry can rack. Can anyone reccomend a good place to buy Nato cans with metal lids and spouts? Also, anyone know of a good Jerry Can mount system that can be purchased and welded to a carrier? Thanks for checking out my thread.

  6. #56
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    Looking great...I like the upturn around the grille too. Nice touch!
    Red XJ's FTW
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  7. #57
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    Quote Originally Posted by GregB_00XJ View Post
    Looking great...I like the upturn around the grille too. Nice touch!
    Thank you! The upturn was the hardest thing to figure out. The front bumper is almost done, and the rear bumper is tac welded together. I just have to find some time to post, been too busy working!! Thanks for looking!

  8. #58
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    Feb 2011
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    Default Rear bumper design

    Well guys and gals..... the last few weeks have been an absolute whirlwind of activity. I made the crazy decision to try and get the rig done enough (in my opinion) to roll to the Overland Expo. A friend of mine who used to work on our Rally car team became a rep. for Engel Fridge/Freezers, and he said if my rig would be done that he would have it placed in the Engel booth at the show. That was motivation enough to spend every waking moment not doing my regular job working on the Jeep to prepare it for the show. So I elected to slack on the posting, and fire up the fab shop every night at 6pm, and run until I couldn't run anymore. This entailed lots of Dubstep at rediculous volume (sorry to neighbors), RedBull and the help of a few good friends to make it come to fruition.

    At this point we have already done 6 days in the vehicle, and man oh man are we pleased with the results. Like any vehicle the laundry list of things to do is ever growing, but that will have to come in later posts. First, I wish to bring you up to speed with the progress. Keep in mind that I was much less focused on taking photos, and way more focused on just getting the job done, so you will have to excuse the night photos when I get there, I am not terribly good at taking photos at 3 or 4 in the morning lol.

    When we left off before, we had completed the front bumper design, and were just starting to lay out the rear bumper. I grabbed the foam core board and the razor, and started dreaming up a design First things first though, I have to remove the factory bumper and mounts...

    This turned into a serious PITA, and I had to use this...



    To heat and remove these...



    so I could get these off...



    Anyone who owns a ZJ knows the fuel filler goes through the "frame" just in front of these nuts on the drivers side, so It was likely one of the most sketchy things I have done in years in my fab shop. I of course added tons of heat shielding before shoving the rose bud down the frame rail, but it scared the bejesus out of me regardless. Finally the brackets and hitch were off!



    The next step was to open up the holes in the rear of the frame, and make room for the brackets



    so out comes the die grinder or cut off wheel and the sparks were flying once again.... the holes were opened and ready for a mock up bracket



    I decided to do some flat brackets on the bottom that would bolt through the stock holes as well as some verticle brackets that I would eventually weld to the flat bottom plates, and bolt through from the side. I wanted more than just 2 bolts per side, especially with a sparte tire carrier planned for this bumper. I did some figuring of angles, and sheered up the vertical brackets and put them in place



    I used the RC Car tire foams to keep them snug against the side of the frame so I didnt have to drill them and bolt them in for now



    At last, I was to the fun part, a blank canvas, time to get creative!


  9. #59
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    Default Rear bumper design cont.

    I had already made the basic decision on the rear most part of the blade. That is determined by the shape of the rear bumper brackets. So to start I just had to measure and shear the appropriate size pieces for the brackets, and tape them in place. First the top plate.....



    Then The rear plate..



    You will probably notice a 90 degree section that is open in between plates, that is meant to be the weld area once these plates are transfered to steel. The bottom plate was next on the list..



    The main blade is somewhat laid out...



    This is where the serious head scratching starts to set in. I have been avoiding facing the fact that I had no idea what I was going to do on the side of this vehicle for the rear bumper. Truth be told, I was literally and completely lost. The problem is the size (height) of the space that needs to be masked or covered. I don't see the point in putting so much extra weight in material there, yet it has to be covered and or protected, or it will look un-finished. I did what any fabrication hack would do, and that is to start making parts. When all else fails, build something, then make it work I decided to start with the top profile, as that would be the same regardless of what I do below....



    Even though it is not reflected in these photos, I decided to make the outside line straight from under the tail lamp to the front point of the rear bumper, this would save the number of plates that I need to make, even though the bend would have been cool and would have added more character



    Due to the fact I was still at a loss on what to do with the sides, I just started making more pieces, like these under the tail lamps



    I figured I would just start filling in the blanks until it was completed. The funny thing abnout plate bumpers is how easy it is to "paint yourself into a corner", where you can't make the angles match up. I was very worried about this, and the overall esthetics, but I figured I didn't have much choice, so I just kept going.

    Here are the upper side panels...



    I had finally reached that critical moment, where I needed to decide the angle of the bottom plate. In my opinion it had to kick in toward the center of the vehicle, as it would have looked way to squared off to run it straight down at the same exact angle.


  10. #60
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    Default Rear bumper design cont.

    choosing the angle would force me to commit, and there was no turning back. I decide to change the angle on the lateral plane first , this would kick the rear of the bubper in, and make it not so squared off. I simply followed the line from the top plate all the way to the rear of the vehicle...




    I estimated the angle that I wanted on the sides and drew that angle into the vertical surface and cut it



    The last and final 2 cuts were determined by the angles I put on the lateral and verticle plates. I just held up a straight edge and marked the cut lines, then cut them. I did add some angle to the bottom plate for extra clearance in the back corners



    Then it was as easy as adding the side plate to fill in the blank



    I ended up trimming the bottom of that last plate significantly in order to make the overall height of the bumper much shorter, this became a necessity when I added the side plate



    The result isnt that bad, I figured it would take some time to grow on me, as I have not been a big fan of this rear bumper situation





    I only did one side of the rear bumper, and was just going to hope I measured correctly and it would be semetrical in the rear

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