Flight Control Tower stripped on one side

[AirTool]

To resurrect an old thread for anyone that has a striped tower bolt. Big thanks to "Bchesley" and previous posters. This why I'm such a big fan of this site.

I have a 2001 Air Nautique with a Gen 2 FCT tower. One of my tower fold down bolts was striped out. I used a Helicoil and fixed both sides in about 30 minutes. I've never used a helicoil and it worked perfectly. I bought a 3/8 x16 helicoil kit on Amazon (http://www.amazon.com/gp/product/B0002SRDVE) for $15 and got it 2 days later. I had to buy a 25/64th" drill bit to drill out the existing threads and some red Loctite. I used two helicoils back to back to make sure i had a long enough thread for the bolt to hold securely... One of the easiest fixes I've done.

Thanks for the help.

How hard was it to drill down the original center line? i.e. to be sure the hole was plumb for lack of a better word.

[House324]

It was no problem. The existing hole is only a little smaller than the drill bit, so it naturally follows the existing hole. Just use care to drill it in as straight as possible because aluminum is soft, but it easily goes in straight if you are close. Just go a little slow because the drill bit will bite into sides of the hole and want to jerk you around a little.

[House324]

[House324]

Sorry if it's a little blurry...Only had my phone camera. In the first pic, I was testing the Helicoil to make sure it fit the 3/8" locking bolt. Second pic shows striped out threads. The third pic shows the hole after it was drilled out. Fourth pic, cutting with tap. Use oil or cutting fluid for lubricant. Start firm, but slow, to make sure it goes in straight. Occasionally backing it out to vacuum out metal shavings. Last pic, finished threads. I carefully sprayed out the oil residue with brake cleaner and vacuumed it out to make sure the loctite would bond with the metal. Finally, I put anti-seize grease on the bolt after the loctite cured and re tightened.

[MAK]

Nice thread. I've got my Heli coil ordered up from Amazon so I can get this done before next weekend. How have they held up thus far? In the past I have had to take the tower down quite frequently but now I've got a shop where I don't have to. Hoping it stays nice and tight!

[Txpilot83]

So this just happened to me last night with my New Dimension FCT clone. I called ND towers and they recommended I try re-tapping the treads with a 3/8"x16 tap before going the Heli Coil route. (I first used a DeWalt tap from Home Depot but I couldn't get it deep enough, ended up buying a tap set from Pep Boys that had one that worked) My re-tapping seems to be a perfect fix and saved me the trouble of doing the Heli Coil. I also called Buxton Marine and they quoted me only $150-$200 bucks to do the Heli Coil fix. That seemed like a great deal to me and if my easy re-tapping doesn't hold I'll be taking it to them.

Heres a few trips I was given to keep this from happening again:
-Always use anti-sieze on the bolts
-Mark sure the bolts threads don't have debris in them, and if they do use a steel hair brush to clean them
-Make sure the threads in the hole are clean, I found a winchester 270 cleaning brush fits great
-Tighten both bolts down tight (I don't think I tighten one side enough yesterday and the rough lake jarred the bolt and messed up the threads)

Hope this helps

[jkallen21]

FWIW - I had to re-tap my FCT as well because the bolt broke off inside. I considered the Do-it-yourself route (drilled out the old one myself), but opted to use the machine shop for the re-tap. Best $50 I've spent on that boat. I would suggest you leave the cover on the boat to do this. Lots of metal shaving would have fallen into the boat which don;t mix well with bare feet in the summer!

[skibum1110]

How does the helicoil work if the tower is up and down all the time?

[kend]

How does the helicoil work if the tower is up and down all the time?

Helicoils are much stronger than the original metal; if it is installed correctly (don't cheat on drill bit size) it will be better than factory. Many parts on airplanes are originally built with coils because it is stronger.