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  • Door frame alterations

    I switched tracks a bit to working on the doors. Before I can continue building the front clip sub-structure I need to know the size and location measurements for the vents located on top of hood. I need these measurements as I plan to run sub-structure members around the vent edges and thus provide mount points in the middle of the front clip skin. Itís going to be a couple of weeks before I can get the needed vent measurements so I went to the next item on my build list which is the doors.



    The doors relate to the front clip in that they are adjacent panels but on the Miura there is also a common rocker panel, silver in the rendering above, that extends from the front wheel opening under the door all the way to the rear wheel opening. So it will be important to know the exact rocker panel height and thus where the top edge of this rocker panel will be under the front clip. The door bottom is the main constraint on rocker panel height and the door bottom is constrained by door hinge location and side window lift location.

    As a reminder, Iím using the door frames, hinges, and side windows from a 1991 C4 Corvette. The Corvette doors are taller by 5 ĹĒ than what I need for the Miura. So I need to remove the bottom 5 ĹĒ from the donor doors and bring the bottom, rear corner forward by 6 ĹĒ. The two main impediments to doing this is that the electric window lift mechanism needs to be shortened and the bottom hinge moved upward. Hereís a door with the new size marked in masking tape and a mock-up of the shortened window lift.



    So now I needed to move the bottom door hinge upward by 1 ĺĒ as it is located too low in the donor door. The main limitation for a new hinge location is the wire harness routing to the door via a rubber boot. By relocating the bottom hinge to snug up under the oval boot hole, it will be real close to providing space for the 5 ĹĒ door chop. Even if I canít get the full 5 ĹĒ, I decided it was better to have the rocker top edge a fraction of an inch lower than to completely re-do the door pillars.

    The door hinges use 3 bolts that screw to the door pillars via a cage nut plate. The cage nut plate is located on top of a heavy L shaped reinforcement plate spot welded inside the door pillar. By drilling out the spot welds, I was able to save and reuse all the hardware.



    The bottom 3 square holes are the original hinge location and the top 3 square holes were cut out for the new hinge location. The reinforcement plate was rosette welded into the new position via the open holes and a sheet of steel placed behind the remaining holes and rosette welded to seal everything up.



    The door frame was easier as I was able to just drill some new holes through it for the new hinge location.



    Here it is with hinges and wiring harness boot back in place. Itís tight but should work fine. I can now start cutting away at the lower door frame.
    Joel Heinke
    Be original; don't be afraid of being bold!

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    • This is simply awesome work! One of the best bios threads on the web, if not the best. Can’t wait to see the progress on cutting the bottom of the doors!
      Luke

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      • Originally posted by luke.jenner View Post
        This is simply awesome work! One of the best bios threads on the web, if not the best. Can’t wait to see the progress on cutting the bottom of the doors!
        Luke
        Luke: thanks for your enthusiastic input!
        Joel Heinke
        Be original; don't be afraid of being bold!

        Comment


        • Man, I cannot wait to see this car's progress!!!!
          Now building in Mooresville NC
          http://www.flickr.com/photos/adrianburton
          http://profile.imageshack.us/user/AdrianBurton
          http://s997.photobucket.com/albums/af91/AdrianBurton/

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          • Door frame transformation

            The next step in the door frame transformation was to bring the bottom rear corner inward by at least 6 ĹĒ. C4 Corvette doors are composed of a spot welded sheet metal frame thatís bonded to and sandwiched between a plastic inner door panel and a composite door skin. Iíve already peeled away the outer door skin so only the inner panel and door frame remain. This close-up shows the Miura door skin edge outlined in masking tape over the door frame to indicate places requiring modification or removal. I donít plan to use any of the plastic inner panel in the final Miura door so I will be cutting it away in pieces when access is needed to the metal door frame for modifications.



            I first drilled out the spot welds between side impact channel and rear of door frame. I then made a pie cut below the door latch mount point to straighten an angled section, sliced off about 6 inches of the plastic inner panel and bent the rear edge of the door frame forward. At this point everything inside the door is now in close quarters. I had to remove some gusset material inside the door frame rear edge to provide clearance for the side window to be lowered. After a few rounds of trial fitting the door and side window in place and measuring everything multiple times, I put in a few tack welds to hold the door frame together in the desired shape.



            The long end of the side impact channel will get cut off once Iím sure about the modifications and itís ready for final welding. Part of the verification process is making sure the side window glass wonít be touching metal when itís fully retracted and when being raised. I thought the angled corner shown in the following picture had insufficient clearance and wanted to do something about it.



            Iíve been told that tempered glass cannot be cut and side window glass is tempered. I could compromise by taking away some of the door rear edge angle and thus free up some space inside the door frame. Alternatively, if I could just remove about ĺĒ from that corner of the glass I could get the needed clearance and keep the Miura signature door rear edge swooping angle.

            My son does lapidary (stone cutting, shaping and polishing) for a hobby. He has some nice industrial diamond tooling for shaping stones which turn out to be just about the same hardness as tempered glass. Specifically, he has a motorized grinder/polisher somewhat like a bench grinder but it has diamond encrusted wheels the coarsest being 80 grit. I figured what the heck; letís give it a go, the worst that could happen is weíd end up with a bunch of shattered glass. Well it turns out you can fairly quickly grind away tempered glass with the right tooling.

            This same window corner was also making for a clearance challenge when the window is partially retracted with that corner in the door latch area.
            My first thought was to use a narrow ďbear clawĒ latch to avoid the clearance issue. This would work but Iíd much rather used the wider OEM Corvette door latch because it provides for external and internal door lock to latch interfaces. It turns out that with the window corner ground away; the door glass now just clears the Corvette door latch. Itís tight enough that I think some thin nylon shielding might be needed to ensure no glass to metal contact but I think it will work.



            My final check was to mockup the door rear edge in cardboard.



            Itís looking good! I need to have at least a ĹĒ flange on the door frame in order to clamp an aluminum door skin to it. I plan to encase the door frame in aluminum sheet and the flange will be part of that. So hereís my final check to see if thereís adequate space for the flange. It looks like it.



            More to come on door frame transformationÖ
            Joel Heinke
            Be original; don't be afraid of being bold!

            Comment


            • Originally posted by AdrianBurton View Post
              Man, I cannot wait to see this car's progress!!!!
              There you go Adrian, hopefully this wets your appetite
              Joel Heinke
              Be original; don't be afraid of being bold!

              Comment


              • definitely and for the record I am always looking for the tips and tricks that you are utilizing
                Now building in Mooresville NC
                http://www.flickr.com/photos/adrianburton
                http://profile.imageshack.us/user/AdrianBurton
                http://s997.photobucket.com/albums/af91/AdrianBurton/

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                • Originally posted by C5GTO View Post
                  Vinny: are you going the composite or aluminum route with your CLK-GTR build?
                  Hey Joel, I'm making the body in aluminum, the tube chassis is steel with the cabin covered with riveted aluminum panels.
                  -Vinny
                  Remember, there is always next year.

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                  • Too much of a good thing

                    So I was taking another look at the clearance between the now trimmed side window glass and the door latch. A thought occurred to me that if I just removed another 1/8Ē it would provide a good safety margin of clearance space. So I pulled out the side glass and took it over to the lapidary grinder/polisher. Iím grinding away and Ö

                    I think you can see where this is going and should have left good enough alone.

                    Well, I can now speak from firsthand knowledge that tempered glass is very stable until it isnít. It can be instantaneously explosive! One second you have a full pane of glass in your hands, the next second your hands are holding air and the tempered glass is now thousands of shards spread across the work area blast zone. I guess the good news is that I didnít get cut by all that flying glass.

                    I do know what I did wrong, I think. I think the grind contact zone got too close to the edge of the diamond wheel. My son says he stays away from the wheel edges as the diamonds there can ďgrabĒ a stone out of your hands and basically trash it. I think either the sharper diamonds or maybe the wheel edge itself started a chain reaction fracture that blew-up my glass.

                    The other good news is that I was able to find a matching set of C4 Corvette side windows on eBay for $160 shipped. So this learning opportunity cost me something, but itís really not that expensive of a lesson, yet. Cross my fingers that I can grind that corner off the new glass without an explosive outcome
                    Joel Heinke
                    Be original; don't be afraid of being bold!

                    Comment


                    • Yikes!
                      Glad you're okay Joel.
                      Did that get your heart started or was it one of those things that happened so fast it was over before you even knew what was happening?

                      Comment


                      • Originally posted by C5GTO View Post
                        ...Cross my fingers that I can grind that corner off the new glass without an explosive outcome
                        HmmmmÖ I didn't know you could grind tempered glass. I did learn that flat tempered glass looks just like regular flat glass, but you can only cut one of them. Luckily when it explodes it's usually in a shower of tiny little squares that aren't too sharp. Ka-Boom!

                        Comment


                        • Originally posted by 20below View Post
                          Yikes!
                          Glad you're okay Joel.
                          Did that get your heart started or was it one of those things that happened so fast it was over before you even knew what was happening?
                          Happened so fast I didn't have time to get scared or do anything but stare at my now empty hands.
                          Joel Heinke
                          Be original; don't be afraid of being bold!

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                          • the fact that something pleasant becomes unpleasant because you have or do too much of it: You can have too much of a good thing.
                            My mission: To help you build your best love life.
                            Shadi todne ka wazifa | Nikah todne ka wazifa | Wazifa for Love Marriage

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                            • Door frame transformation (cont.)

                              While waiting for new door glass to arrive, I decided to finish up on the driverís side door frame. The metal was trimmed so it would all fit inside the door. For the picture, I place a length of ĺĒ square tube where the top of the rocker panel will be. The door opens and closes over this just fine.



                              Itís starting to look more like a Miura door especially when compared to what it looked like when the transformation started. Here's the before picture.

                              Joel Heinke
                              Be original; don't be afraid of being bold!

                              Comment


                              • Front Clip Substructure

                                I now have the station buck pieces that I was waiting on prior to building the front clip substructure. I needed the hood vent hammer forms to be completed so I could locate the vents that are on top of the front clip with precision and thus locate the substructure along the vent edges. Hereís the vent hammer forms fitted into the station buck.



                                To build the front clip substructure, Iím basing all fore and aft measurements off the front axle centerline. The station buck has a transverse station located on the front axle centerline so itís easy to take measurements from that point. All vertical measurements are based off the garage floor which has a slight tilt to it with the passenger side about ĹĒ lower than drivers side. The chassis is set to targeted ride height and dead horizontal using blocks and shims. So Iíve determined the height of various chassis members relative to the garage floor under the drivers side tire and all vertical measurements will be taken from these chassis members with some math addition involved.

                                As a reminder, I had prior built the hinges for the tilt up front clip.



                                The front clip substructure originates at the hinge and goes back to the windshield to support the front clip skin. Hereís what the steel substructure looks like on a factory Miura.



                                I am electing to build the substructure in aluminum on my car so I canít just copy the original. Instead of a pure sheet metal substructure as was done on the original, Iíll be using a combination of rectangular aluminum tubes and sheet. My objective is to locate the substructure just under the front clip skin and I could not accomplish this without having an accurate station buck. I take multiple measurements from the station buck to ensure each substructure member is positioned just under the intended skin height as it changes elevations.

                                I started by using a piece of wood to mockup the substructure member going in front of the hood vents. Itís height and location was set using blocks and clamps. From there, I connected the dots with a rectangular tube.



                                From there, a tube was added to extend this just beyond the front bulkhead. Again, I had to take many measurements to ensure this member would stay below the skin. It does except for the aft 6Ē which Iíll lower that section with a small pie cut and weld. It was then repeat for the drivers side.



                                Thatís it so far. More to come as I progressÖ
                                Joel Heinke
                                Be original; don't be afraid of being bold!

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