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Old 02-11-2012, 11:45 PM   #1
Charles67
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In the Pittts and other airplanes the covers for the wing and fuselageinspection holes are secured to plastic rings built in the fabric using twoPK4 screws. The screws engage into little brackets riveted to the covers.If I don't tighten the screws enough, they get loose and fall off. If I tighten the screws a little too much, the holes in the bracket get larger and it becomes impossible to tighten the screws (like a stripped thread, even if there is no thread in the bracket.Any suggestions about a particular type of glue or any other method to solve this problem?Thanks


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Old 02-12-2012, 12:14 AM   #2
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Put a nut plate on the little bracket and use a machine screw?



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Old 02-12-2012, 12:21 AM   #3
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I drilled two holes (just a little less than the diameter of the openiing) through the inspection plate and retaining clip. Then I attached a couple of nuts to the backside of the retaining clip over the holes using a little bit of JB weld. Install the inspection cover, install the machine screws to snug and the plate doesn't move fore or aft nor side to side. Works great and haven't lost a plate in a long time. I don't think screwing a PK screw into the plastic ring is a very good idea.
Best regards,
Brad
Edited by: TxSkyBolt

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Old 02-12-2012, 02:56 AM   #4
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The real solution is to use Steen's covers. They are a little larger, but use a spider clip to stay in place. We put them on my Eagle and I love them.

Of course, it's best to do it during the covering stage...

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Old 02-12-2012, 04:50 AM   #5
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Quote:
Originally Posted by Charles67

In the Pittts and other airplanes the covers for the wing and fuselageinspection holes are secured to plastic rings built in the fabric using twoPK4 screws. The screws engage into little brackets riveted to the covers.If I don't tighten the screws enough, they get loose and fall off. If I tighten the screws a little too much, the holes in the bracket get larger and it becomes impossible to tighten the screws (like a stripped thread, even if there is no thread in the bracket.Any suggestions about a particular type of glue or any other method to solve this problem?Thanks
I am having difficulty trying to visualise what you are explaining. Can you send a picture in?
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Old 02-12-2012, 06:06 AM   #6
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Thanks. I will keep this in mind for the next fabric recovering.
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Old 02-12-2012, 05:27 PM   #7
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It is a pretty common set-up. The plasting ring is glued to the fabric. The black clip (or bracket) is flexible and can be bent to go under the plastic ring, when the cover is placed on the inspection hole. Two PK screws go through holes in the cover and in the fabric/plastic ring and attach to the clip. The problem is that there is no nut, so the screws thread in the clip only and that does not work very well. The photo shows one loose ring and one ring assembledwith the cover and the cover clip. Screws are shown in correct positions, but not thrededthru holes
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Old 02-12-2012, 05:28 PM   #8
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Thanks. I will give it a try
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Old 02-12-2012, 09:20 PM   #9
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Quote:
Originally Posted by TxSkyBolt
I drilled two holes (just a little less than the diameter of the openiing) through the inspection plate and retaining clip. Then I attached a couple of nuts to the backside of the retaining clip over the holes using a little bit of JB weld. Install the inspection cover, install the machine screws to snug and the plate doesn't move fore or aft nor side to side. Works great and haven't lost a plate in a long time. I don't think screwing a PK screw into the plastic ring is a very good idea.
Best regards,
Brad
I agree with Brad, don't put screws through the plastic ring, it weakens it and makesinstallationmuch more difficult than it has to be, make the holes in the cover and the retaining ring to go just inside the plastic ring. Instead ofgluinga nut on like Brad did, Idrilledand tapped the spring for a 4-40 screw and used stainless 4-40 machine screws and none have stripped so far. Much more secure than the PK screws.
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Old 02-13-2012, 02:06 AM   #10
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One question: how many threads were youable to tap in the spring? My springs arethin.Thanks
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Old 02-13-2012, 02:31 AM   #11
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Quote:
Originally Posted by Charles67

One question: how many threads were youable to tap in the spring? My springs arethin.Thanks
I don't know, but I have done this on several different kinds of inspection covers, so I am sure I had the same thin springs as you and have never had an issue with it. I have never stripped one out and they don't loosen up. Initially, I unriveted the spring and riveted nut plates on which works great, but it is a lot of work, I tried just tapping the spring and that works just as well and is a lot less work.
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Old 02-13-2012, 03:30 AM   #12
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Many thanks
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Old 02-13-2012, 04:50 AM   #13
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Is it possible that you can get your hands on a plate like this?It has 4 springtabs that clamp it tight to the plastic ring. I should think better than two. more evenly spaced and uniform clamping pressure. And no pk screws to hold in place. When the spung steel tabs get bent / loose, it's time to replace. This is what I done with mine. Now, I remove my plates before I have the airplane annualed. I take very good care removing and replacing. It sucks when I have to paint new covers because of bent clips.These are from American Champion Aircraft. Got them for my Citabria.The ones from Steen, I think,are much better, but you need to install the plastic ring at the time of fabric covering. The ringhas a step shoulder to betterposition the cover before it is screwedup snug and tight .


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Old 02-15-2012, 11:33 PM   #14
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guess ive been lucky, still have the 2 tang covers with the pk screws,and havent lost more than a couple and they were loose to begin with,,,but where im going with this,,is a friend of mine recomended the "non-slip" recessed type cover aircraft spruce p
09-18740...they drop into the plastic retainer and dont "slide" at all..maybe an option

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Old 02-16-2012, 12:02 AM   #15
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I lost a couple of those, so they can move

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Old 02-16-2012, 03:39 AM   #16
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Thanks to all for the valuable comments and suggestions.
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Old 02-22-2012, 08:57 PM   #17
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An aircraft mechanic today suggested using two tinnerman nut plates on the inspection ring opposite of the clip, then drilling a hole in the inspection plate securing with two sheet metal screws.
Seems to be easy. No riveting orgluing. Easy to replace tinnerman nutplate if it gets loose over time.

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Old 02-23-2012, 02:54 AM   #18
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Many thanks for this additional suggestion.


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