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-   -   K1100 Nut Plate Question (https://vansairforce.net/community/showthread.php?t=83084)

Mike S 02-28-2012 09:52 AM

Quote:

Originally Posted by rockwoodrv9 (Post 634027)
I am a new builder so I don't claim any knowledge, but what is the point of dimpling or countersinking any nut plate other than that is what it shows on the plan? I have a hard time seeing that a dimpled or countersink rivet would be any stronger than a regular rivet.

Has nothing to do with the strength of the rivet, it is all about having a flat surface on top of where you mounted the nutplate.

You do not want rivets sticking up and interfering with the part you are going to be attaching with a screw.

Bob Axsom 02-28-2012 10:05 AM

I see a little need for more exposure here
 
Quote:

Originally Posted by rockwoodrv9 (Post 634027)
I am a new builder so I don't claim any knowledge, but what is the point of dimpling or countersinking any nut plate other than that is what it shows on the plan? I have a hard time seeing that a dimpled or countersink rivet would be any stronger than a regular rivet. In fact, I think you could make a good argument that because more metal is there with no countersink that it would be stronger left alone. All the rivet does is keep the bolt or screw from spinning. What the head of the rivet looks like does not matter.

Is it just one of the things required to meet the 51% rule like having to fabricate shims and other little pieces that could easily be included with the rest of the kit?

Did Mike's absolutely correct answer clear things up for you? It is very important to understand the concept before you start installing platenuts in your airplane.

Bob Axsom

Bob Axsom 02-28-2012 10:13 AM

Well when that happens
 
Quote:

Originally Posted by Capflyer (Post 633942)
Some good best practices here...thank you all. I've certainly done my share of tool mods so grinding down the sides is a "duhhh" for me, not sure why it hadn't hit me before. I like the idea of the smaller diameter ones as well from Cleveland. My only concern with countersinking the mounting holes if if you go just a tad bit too far the rivet head will not hold but in general not a bad idea.

Well, when that happens like a sitiation where you have to drill out the mounting rivets to replace a fixed platenut with a floating platenut you get to practice Maretial Review Board salvage. My MRB action was to enlarge the mounting holes to #30 (yes those in the platenut as well) and use 1/8" dia flathead rivets in place of the 3/32" dia rivets It doesn't change the form, fit or function of the assembly.

Bob Axsom

WenEng 02-28-2012 10:41 AM

Try countersinking a tad too far on scrap....
 
(For nut plates)... you can see that the rivet will "backfill" somewhat and often make an acceptable squeeze. If you countersink for nas1097 rivets and you went too deep, keep going for a normal 426ad3 rivet. I often got the required depth just using the hand deburring tool with the countersink bit. You sure dont need much for those tiny heads. You quickly learn the right looking depth.

rockwoodrv9 02-28-2012 10:43 AM

nutplates
 
Quote:

Originally Posted by Bob Axsom (Post 634035)
Did Mike's absolutely correct answer clear things up for you? It is very important to understand the concept before you start installing platenuts in your airplane.

Bob Axsom

Like I said, Im a new builder. I only know what I have had to work with so far. The only nutplates I have installed are on the spar of the rudder, which also has a backing plate. There is no dimpled skin or anything that would cause the nutplate to not have perfect contact with the backing plate. There is nothing that could ever come in contact with the 1/8" rounded head of the rivet holding the nutplate. Of course, it the skin or metal under the nutplate was dimpled so it interfered with the nutplate keeping it from sitting flat, it would have to be countersunk, but that would be on the underside of the nutplate. Im only on the tail kit and I am sure I will come to a point where it could be necessary to countersink the underside of the nutplate and if that happens, I will do it. My point was so far I haven't seen a place where using a flush or standard rivet to hold the nutplate down made any difference. If there is a reason to use a flush rivet on the nutplates on the rudder, please let me know. I admit I do not have the experience everyone else here has and always open to learn something new - especially when it helps me build a better - safer plane.

krw5927 02-28-2012 10:49 AM

Quote:

Originally Posted by Bob Axsom (Post 634038)
Well, when that happens like a sitiation where you have to drill out the mounting rivets to replace a fixed platenut with a floating platenut you get to practice Maretial Review Board salvage. My MRB action was to enlarge the mounting holes to #30 (yes those in the platenut as well) and use 1/8" dia flathead rivets in place of the 3/32" dia rivets It doesn't change the form, fit or function of the assembly.

Bob Axsom

Common MRB practice on the big certified boys as well.

Mike S 02-28-2012 10:53 AM

Quote:

Originally Posted by rockwoodrv9 (Post 634052)
The only nutplates I have installed are on the spar of the rudder, which also has a backing plate.

Now I understand what is causing you a bit of confusion.

The nutplates you have are for the rod ends that are used as pivot bearings for the rudder. They are probably i/4" or 5/16" thread size. There is not an issue with clearance there.

Later, you will be installing a lot of #6. and #8 size nut plates, which will be used to fasten a part flat on the part the nutplate is mounted to, like inspection covers, or the fairing at the tail. In this case, the surface on top of where the nutplate is mounted must be flat, thus the dimple/countersink for the rivet.

gasman 02-28-2012 11:03 AM

If you happen to have a Knipex 8603-180 7 inch wrench, just use 426A (soft) rivets for most all of your edge nut plates.

rockwoodrv9 02-28-2012 11:07 AM

got it!
 
Quote:

Originally Posted by Mike S (Post 634062)
Now I understand what is causing you a bit of confusion.

The nutplates you have are for the rod ends that are used as pivot bearings for the rudder. They are probably i/4" or 5/16" thread size. There is not an issue with clearance there.

Later, you will be installing a lot of #6. and #8 size nut plates, which will be used to fasten a part flat on the part the nutplate is mounted to, like inspection covers, or the fairing at the tail. In this case, the surface on top of where the nutplate is mounted must be flat, thus the dimple/countersink for the rivet.

Thanks for the info. Got it now. I read and reread the nutplate instructions and can see where you are talking about. Since I hadn't gotten anything other than those on the rudder spar, I couldn't see that it made a difference on what type of rivet I used. I will look ahead at the plans and see what places I will need to use dimpled or countersinking and make sure I have it figured out first. Thanks.

Mike, now would be a good time to be in Cameron Park. We got 12" of snow so far last night and it is still coming down like crazy. My satellite dish is covered and we are not getting TV! ugg!

Mike S 02-28-2012 11:32 AM

Quote:

Originally Posted by rockwoodrv9 (Post 634074)
Mike, now would be a good time to be in Cameron Park. We got 12" of snow so far last night and it is still coming down like crazy. My satellite dish is covered and we are not getting TV! ugg!

Oh well, at least your internet hookup is still working:D


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