Nacra 5.2, Sheared off bolt in hull - anyone used a bolt extractor successfully?

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Nacra 5.2, Sheared off bolt in hull - anyone used a bolt extractor successfully?

pairajacks

Rank: Lubber

Registered: May 11, 2011

Last visit: May 31, 2019

Posts: 37
Posted: Feb 23, 2016 - 02:24 AM

While disassembling my Nacra 5.2 for some hull repair this winter, I sheared off one of the bolts holding the front crossbar (specifically the inboard strap aft of the main crossbeam). I'm planning to use a bolt retractor, but thought I'd check first to see if anyone has had any better ideas/experience.

Alternatively, I think I'd have better luck driving the remaining bolt stem past the nut and make it drop out.... does it have any room to drop out or is it in a blind cavity?
(before breaking, I was able to loosen the bolt many turns (about 1/4" gap) before it started getting tight. I worked it in and out a bit, then got impatient and it sheared off flush with the hull. ). Next time I'll use grease or anti-gall :)

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Pairajacks
1985 Nacra 5.2
Corvallis Oregon
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arch

Rank: Mate

Registered: Jan 25, 2004

Last visit: Apr 06, 2021

Posts: 267
Posted: Feb 23, 2016 - 09:20 AM

i've used 'bolt extractors' successfully a few times on car engines and it worked great. the hard part is drilling into the center of the bolt since the drill bit tends to slip around as you're drilling. since your bolt was tight enough to shear off in the first place, use some penetrating oil on the threads first and let it sit for an hour until the oil works it's way down into the threads before attempting to unscrew it. then take it slow.

if this method fails and you have to resort to drilling the bolt out, you can restore the threads with 'fix-a-thred' by alcoa or any helicoil thread repair product. i've had to use this a couple of times and it's quite effective. i used 3/8-16 size with a 13/32" drill bit. my bolts were 3/8".

http://afs-fix.com/fix-a-thred/04.htm
https://www.youtube.com/watch?v=b96y5It50Yo

good luck!
j

Edited by arch on Feb 23, 2016 - 09:38 AM.

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Aquacat 12 (sold)...'87 Nacra 5.8 (sold)...'03 Nacra Inter18 (sold)
Venture 15 (sold)....'89 Nacra 5.8 (sold)...'91 Nacra 5.8NA (sold)
'99 Nacra Inter20 (sold)
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onekiwi

Rank: Mate

Registered: Oct 24, 2013

Last visit: Jul 22, 2024

Posts: 251
Posted: Feb 23, 2016 - 11:39 AM

Yep impatience will get you everytime! Make sure you some sort of anti-seize when you put it all back together, stainless on stainless can be a bear sometimes

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Carl

Dart 18x2
Nacra 5.8
Acat
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

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Posts: 7090
Posted: Feb 23, 2016 - 12:22 PM

i have hexicoiled many bolt holes - great system

I use Tef-Gel on all bolts and metal-metal
works amazing
todde

Rank: Lubber

Registered: Sep 15, 2015

Last visit: Feb 23, 2016

Posts: 1
Posted: Feb 23, 2016 - 05:57 PM

As Arch says, center drilling is the tough part. Use a punch to very carefully dimple the center of the bolt. Oil the threads, then carefully drill a center hole with a small bit. Size up the bit to the recommended size for the ezee out and viola, you should be good to go. If you fail to remove the bolt, keep sizing the drill bit up until you are really close to the threads and you should be able to push and pick the remaining bolt out of the threads. Send a tap through to clean the threads. If you are off too much and hit the threads with the drill, hexicoil away!
If you take your time, it really isn't that bad.

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Todd
Bellingham, WA
Sailing Lake Whatcom and Puget sound
Current boats: Hobie 21SE, NACRA 5.8, Hobie 16
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pairajacks

Rank: Lubber

Registered: May 11, 2011

Last visit: May 31, 2019

Posts: 37
Posted: Feb 26, 2016 - 02:25 AM

Thanks for all the replies. Does anyone know if there's any room below the nut to push it out. It might turn out easier to drive it thru instead of out.

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Pairajacks
1985 Nacra 5.2
Corvallis Oregon
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Edchris177

Rank: Chief

Registered: Nov 26, 2009

Last visit: Aug 10, 2024

Posts: 2531
Posted: Feb 26, 2016 - 11:22 AM

Here is an album I made showing the inside of the 5.2 hull.
You would have to install a hatch to replace the nut if you drove it through, & might do quite a bit of damage in the process, requiring more work.
I would try as TODDE says above, if it works, it's way less time spent than installing ports etc.
http://www.thebeachcats.c…pictures?g2_itemId=82844

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Dogboy

Rank: Mate

Registered: Mar 19, 2004

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Posts: 964
Posted: Feb 26, 2016 - 01:21 PM

He's just talking about driving the broken part of the bolt through (into the hull), not doing anything with the nut/plate. From your pics, it looks like he could do that no problem. Whichever way you can get the bolt to turn to get it out of the plate should work.

sm
JohnES

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Posted: Feb 26, 2016 - 07:56 PM

No a hard thing to do.... and you'll need to take your time..

Get three new drill bits.... small, medium, and the size of the ex-out your going to use... starting with the small bit start drilling slooooooooly and get abou a 1/4 inch in.... next size bit... do the same thing and be sure to go sloooooooow... and go a little deeper...

Get you full side bit in there, go deeper add in your EZ out and life will be good again...

AS for replacing you may have to re-tap the aluminum screw plate.. no big deal common problem with NACRAs

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John Schwartz
Ventura, CA
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pknapp66

Rank: Mate

Registered: May 09, 2009

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Posted: Feb 27, 2016 - 10:26 AM

The most important part of this process is not heating up the bolt that you are drilling. Stainless will work harden in a heart beat and will make it very difficult to drill. Go as slow as possible and keep stopping to let
everything cool down. Best luck that I have had drilling stainless is to use plain water as a coolant and plenty
of it. Take your time and expect to helicoil the hole. You most likely galled the threads and locked the bolt
and then broke it. The easy out extractor won't get as good a bite as you had with a wrench or socket. Sometimes you can get lucky and drill the bolt very close to the threads and collapse it inward and pick it out.
Good luck with it.

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Pete Knapp
Schodack landing,NY
Goodall Viper,AHPC Viper,Nacra I20
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arch

Rank: Mate

Registered: Jan 25, 2004

Last visit: Apr 06, 2021

Posts: 267
Posted: Feb 28, 2016 - 05:54 PM

QuoteDoes anyone know if there's any room below the nut to push it out. It might turn out easier to drive it thru instead of out.

pairajacks,
not sure what you mean by 'nut'?
in my experience, there is no bottom to the bolt hole that would stop the bolt from dropping into the hull. you'll find there is no 'nut' on the bottom of the bolt but a threaded sleeve that the bolt is screwed into. that sleeve is cast into the fiberglas and if you hammer the bolt in you will do some major damage to the hull before you're through. do all you can to drill it out first.
j

--
Aquacat 12 (sold)...'87 Nacra 5.8 (sold)...'03 Nacra Inter18 (sold)
Venture 15 (sold)....'89 Nacra 5.8 (sold)...'91 Nacra 5.8NA (sold)
'99 Nacra Inter20 (sold)
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