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Broken bolt in a nut plate, broken bit inside bolt

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  • Body / Glass: Broken bolt in a nut plate, broken bit inside bolt

    The Albatross Avanti has thrown me a new loop. When I removed the hood to pull the engine, two of the hood hinge bolts broke off, and were very rusty. I should have been soaking both for these past several months, but no, I wait until now to try and extract them. One went to plan, step drilling until I could pick the remains out. No damaged threads!

    But I got greedy on bolt #2 with the smallest drill and broke the thing off inside the bolt just before it pierced the far end. ARRggh! I've been ruining bits trying to get past that other bit with no luck. Of course, the hood is fiberglass, so a torch or welding a nut on is a no go ( or does someone have tips of how to to not light it on fire? And the nut plate is apparently bonded to the hood somehow, with no way to extract it.

    This looks like a smart audience, so I am asking. What do I do?



    Does
    Ron Dame
    '63 Champ

  • #2
    You can dislove the drill bit out with nitric acid or alum but it will act upon the steel too ,AS WELL AS YOUR SKIN so close attention and care is needed. Once it's loose flush with lots of water, then drill as before if you've been carefull and anything is left. Don't worry about the fiberglass it won't bother it.

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    • #3
      If the nut plate is shared by other bolts that did come out, you could use the MIG welder trick. Put a bolt in one of the other holes, and put your ground clamp on that. Direct the wire of the MIG at the busted-off drill bit, and lay down a litttle blob of weld. No more than 2-3 seconds. Allow it to cool, or quench with water. Repeat, again, and again, until you have built up a little pinnacle of weld. Then place a nut over the pinnacle, and weld it onto the pinnacle. Allow it all to cool. Try wrenching it out. If you are really, really lucky the bolt stub will unscrew, saving the nut plate intact. Most likely, though, the pinnacle will break off the stub. Then you can start over. Rinse and repeat. Eventually all those heat/cool cycles will break the rust bond betweeen the bolt stub and the nut plate, and the stub will unscrew. It could take you all day, but it will eventually work.
      Gord Richmond, within Weasel range of the Alberta Badlands

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      • #4
        I would try my "Pencil Die Grinder" and carbide bit to carefully cut through the bolt.a real steady hand is required but its doable. The Albatross saga Continues. Luck Doofus

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        • #5
          Before continuing, how 'bout a couple of close pics for those of us without an Avanti to see exactly what you are up against. Few problems exist that don't have a solution...however, sometimes there is no easy solution.
          John Clary
          Greer, SC

          SDC member since 1975

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          • #6
            If It's built like a corvette fiberglass hood you could get a nutsert and drill to what ever size you need for that to fit and install the nutsert.

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            • #7
              It's been a while. If it is a floating 'plate' just slit the fiberglass on the lower side. ( less seen ) and remove it. If they are square nuts floating in a cage, they may not be that easy. If they are 'glassed into' the hood good luck. ( really bad design) You may use anti seize to prevent this in the future.

              Just cut it out, and glass in a new one if it does not come out.

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              • #8
                Originally posted by swvalcon View Post
                If It's built like a corvette fiberglass hood you could get a nutsert and drill to what ever size you need for that to fit and install the nutsert.
                the problem with that is I can't get through the broken drill bit.

                My thought are that since the paint is terrible, go ahead and drill a hole from the top of the hood, drill from that side untill I clear the bolt, then repair the fiberglass.
                Ron Dame
                '63 Champ

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                • #9
                  Why cut the top when you can cut the bottom? The repair will be covered by the hinge.

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                  • #10
                    Ron

                    This is the plate you are dealing with. It's riveted to the bottom hood panel and then the top is glued on. I'll leave the repair up to you but I might just go in from the top. Not much difficulty with the repair if you don't care about the paint. I'm sure others will have good ideas.

                    I will add that the repair to the top of the hood is in an area of stress so you could try going in from the side and removing the welded in nut. It would be hard to weld in a new nut but a rivet nut could work through the old hole and the repair would be out of sight.

                    Click image for larger version

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                    Bob
                    Last edited by sweetolbob; 04-13-2019, 11:56 AM.

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                    • #11
                      Is there room to get a magnet between the inner and outer panel then grind off the rivets and pull the plate out. Repair it and slide it back in and install new rivets? If not cut the hinge side and do the repairs there. If not perfect it's not like it's on top of the hood and you have to look at it all the time.

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                      • #12
                        You might be able to get it out with a left hand drill. Worth a try for a dollar or two.

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                        • #13
                          Click image for larger version

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ID:	1727614I think Bob is closest, though this appears to be a 1/4" threaded plat on the blind side. It seems to have some rivets, but I don't know.
                          Ron Dame
                          '63 Champ

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                          • #14
                            Click image for larger version

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ID:	1727615here is another view.
                            Last edited by Ron Dame; 04-13-2019, 01:14 PM.
                            Ron Dame
                            '63 Champ

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                            • #15
                              This hinge is above the battery, so I am not surprised they were corroded.
                              Ron Dame
                              '63 Champ

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