I don't necessarily know what I'm talking about in the aviation area, but I do home-shop machining as a hobby and have faced things like this before. When I have a hole that has buggered or pulled-out threads, I drill it out to a larger size, tap it and install a bolt or a piece of threaded rod using JB Weld on the threads. Then after the JB Weld sets, I cut it off flush (and file, etc., if necessary), then drill and tap the hole again. This gives you a virgin surface, and since it's steel rather than alloy, those threads won't pull out.
Mike Taglieri On Wed, Oct 28, 2020 at 4:58 PM Flesner via KRnet <krnet@list.krnet.org> wrote: > > > Update on fuel leak fix. I did a test today on the Poly-Nuts and they > are not up to the task. Placed a scrap piece of aluminum in the vise > and drilled three holes. Installed Poly-Nuts with puller, then snugged > them down a bit more with wrench. They might tighten up enough to seal > but I installed a bolt from the back side and bottomed out the threads > to duplicate removing a bolt some day if the threads seize up. I set > the torque wrench to 72 inch pounds, thinking that is a pretty low > setting (6 foot pounds) and the Poly-nuts spun easily just as several > predicted. > > So, that fix is out. I want to proceed through my other possible fixes > in a manner as to not eliminate the easiest and cheapest fixes as I move > to more aggressive solutions without taking a saws-all to my fuel tank > . These are the order I see possible. > > 1. Go to metric and tap. It seems I'd have to go to a 5.5mm to get the > thread depth I'd need without enlarging the hole too much. 5.5MM bolts > special order? Local hardware store does not carry decimal sizes. > > 2. Question. would the Helicoil be as effective as the Keenserts in this > application? What thread size is the outside of the 3/16 insert and > would there be enough threads in the hole to hold? Can I drill the > threads out of present holes and have enough material to thread a 3/16" > Helicoil? I can get Helicoil kit with 12 inserts, tool, and tap at the > local auto store. Keenserts availability? I'd like to get flying again > this weekend. > > > https://www.oreillyauto.com/detail/b/heli-coil-3878/tools---equipment-16488/hand-tools-16814/cutting---drilling-tools-16542/thread-repair-16906/heli-coil-inserts-19596/ecce6617012f/heli-coil-10-32-inch-sae-thread-repair-kit/55283/4368725 > > 3. Go to 1/4" bolts and Helicoil > > I've spent the price of 6 gallon of 100LL without results. I see the > next fix try being the same. That's two hours of flying in the KR, 300 > miles. I hope this fix doesn't go like taxes, just keep going up with > nothing to show for it. > > No speculation please unless you know what you're talking about. And > I thought this was not going to be brain surgery. > > Larry Flesner > > > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
