Stripped Wood Screws

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bobthebuilder
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Stripped Wood Screws

Unread post by bobthebuilder » Mon Dec 11, 2017 8:56 am

Hi Guys,

The aluminium panel that covers my fuel tank and also sports the windscreen is secured with AN bolts and lovely captive nut plates on the forward section. Structurally, this is sound. The rear portion which forms the sides of the cockpit has a few self tapping wood screws that have stripped, obviously from maintenance over the years. (Fly Baby airframe)

I had thought to drill out all of the screw holes and fit captive fasteners, replacing the screws with countersunk AN bolts. (AN366F Anchor Nut plate)

Does anyone have any better ideas?
I'd prefer to keep the screws, but don't want to drill out and use bigger ones.
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Chalkie
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Re: Stripped Wood Screws

Unread post by Chalkie » Mon Dec 11, 2017 3:56 pm

bobthebuilder wrote:Hi Guys,

The aluminium panel that covers my fuel tank and also sports the windscreen is secured with AN bolts and lovely captive nut plates on the forward section. Structurally, this is sound. The rear portion which forms the sides of the cockpit has a few self tapping wood screws that have stripped, obviously from maintenance over the years. (Fly Baby airframe)

I had thought to drill out all of the screw holes and fit captive fasteners, replacing the screws with countersunk AN bolts. (AN366F Anchor Nut plate)

Does anyone have any better ideas?
I'd prefer to keep the screws, but don't want to drill out and use bigger ones.
You could do that, or you could just hammer in some tapered wood 'patches' using a good epoxy wood glue. Once set, trim off excess, drill pilot holes and refit the wood screws.

Wood is nature's composite. :D
bobthebuilder
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Re: Stripped Wood Screws

Unread post by bobthebuilder » Mon Dec 11, 2017 4:57 pm

I had thought of that Chalkie, but didn't think it was an appropriate aviation fix.

Thanks for the input, I'll see what timber I can find.
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V5 - LEO
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Re: Stripped Wood Screws

Unread post by V5 - LEO » Mon Dec 11, 2017 9:46 pm

......there is a tool that one remove stripped screws with I will look for the name tomorrow.

...try Grabit
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Theuns v V
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Re: Stripped Wood Screws

Unread post by Theuns v V » Tue Dec 12, 2017 7:37 am

I agree, if the member that the screws go into is not a major load bearing member I would drill out the holles just enough to clean up the hole and then go to the hobby shop and get a 30 min cure epoxy that you use to glue in hard wood dowls of the same (even very slightly smaller) size than the holes.
Then redril for your wood screws.
Then remove the scres again and put sone this superglue you got from the hobby place also into the hole, it runs in like water. Let it dry for 30 min and out screw back, the glue makes the thread in the wood dowl much more resistant to stripping and waterproofs it .

T
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Re: Stripped Wood Screws

Unread post by bobthebuilder » Wed Dec 13, 2017 12:40 am

Thanks Theuns, I'll go that route.
The screws are not in the longerons, but in strips glued to the top of the longeron, so it won't have an effect on the structural integrity of the load bearing surfaces.
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Theuns v V
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Re: Stripped Wood Screws

Unread post by Theuns v V » Wed Dec 13, 2017 4:09 pm

Get yourself one of those flat "spade tip" wood drills of the size you want to put the dowl in, they drill a nicel clean hole. Just make sure you do not drill into a loadbearing member.
https://s7g3.scene7.com/is/image/ae235/70469_P?$p$

T

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