Jump to content

Convert Riveted Inspection Panel to Nut Plates


Recommended Posts

I'm in the middle of a panel upgrade that includes two G5s. Tha means running wires in the right wing for the GMU 11 and future roll servo for a  Garmin 500 autopilot once it's approved for short bodies. All of the inspection panels ahead of the spar on my '62C were riveted. I've removed 8 of them leaving only the ones where the fuel tanks (O&N bladders) are. I'd like to convert these to nut plates. Is there any reason I can't? Also since these were round head cherry rivets, any reason I can't use a round or panhead screw, it would save having to dimple the holes in the wing.  My IA thought it would be a good idea to get some feedback from this group. 

Link to comment
Share on other sites

There should no issue with changing from rivets to screws, you’re just allowing easier future inspections.  Mooney has used many fastener variations over the years, rivets, round head screws, countersunk screws, internal and external covers.

Clarence

Link to comment
Share on other sites

I don't know how helpful dimpling the inspection panels would be, unless you had a true dimple die (not just the little dimple sets).  When you use dimple sets, you make two identical dimples and these don't actually sit correctly together--the sheets become separated by a gap, with larger dimples giving you a larger gap.  In addition, the dimpling tends to buckle the surrounding area up a little. 

With a rivet line near the edge of a sheet, you actually have to bend the edge down a little to get the edge to stay flush to the adjacent sheet.  On a small inspection panel, that's harder or impossible to do, so I suspect you'll end up with a noticeable gap between the inspection panel and the surrounding skin.

One solution might be to use a slightly larger dimple on the inspection plate than on the skin, but I don't know if that's something you want to experiment with on your own plane...

Link to comment
Share on other sites

Thanks for the feedback.  I do have access to a rivet squeezer with dimple dies.  I'm finding out there is more to this than I ever thought. For instance, if I'm dimpling the inspection plate and the holes in the wing, are there offset nut plates that conform to the dimples?  How are those spec'd.  I'm planning to use no. 6 screws (heads to be determined), no. 40 flathead rivets for the nut plates, which means countersinking very thin plates.  I have the tool for that as well.  

I really appreciate this forum.  I'm sure I would not be into this major work and cost without the renewed interest I've gotten from all of you.  

 

 

  • Like 1
Link to comment
Share on other sites

9 hours ago, Buckeyechuck said:

Thanks for the feedback.  I do have access to a rivet squeezer with dimple dies.  I'm finding out there is more to this than I ever thought. For instance, if I'm dimpling the inspection plate and the holes in the wing, are there offset nut plates that conform to the dimples?  How are those spec'd.  I'm planning to use no. 6 screws (heads to be determined), no. 40 flathead rivets for the nut plates, which means countersinking very thin plates.  I have the tool for that as well.  

I really appreciate this forum.  I'm sure I would not be into this major work and cost without the renewed interest I've gotten from all of you.  

 

 

You’ll need to buy nut plates with dimpled rivet holes as well, you can’t countersink the very thin skin of the inspection covers.

Clarence

Link to comment
Share on other sites

14 hours ago, Buckeyechuck said:

Thanks for the feedback.  I do have access to a rivet squeezer with dimple dies.  I'm finding out there is more to this than I ever thought. For instance, if I'm dimpling the inspection plate and the holes in the wing, are there offset nut plates that conform to the dimples?  How are those spec'd.  I'm planning to use no. 6 screws (heads to be determined), no. 40 flathead rivets for the nut plates, which means countersinking very thin plates.  I have the tool for that as well.  

I really appreciate this forum.  I'm sure I would not be into this major work and cost without the renewed interest I've gotten from all of you.  

 

 

You can dimple the skin on the inspection plate as well as the rivet holes on the nutplate with the dimple dies.  It will take more effort to dimple the nut plates--you'll need to grind off part of the female dimple die to allow it to clear the center section.  Sorry, I'm away from my toolbox so I don't have pictures, but it'll make sense when you have them in hand.

I don't believe there are standard nut plates that you can buy that are already dimpled for flat head rivets (I might be wrong on that, though).

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.