Wings 38,Total 501-Finished Right Tie Down Bracket

As is always the case, the second time around that you do something, the easier and faster it goes. The right side went pretty well this afternoon. Finished drilling all the bolt and rivet holes, and countersunk the rivet holes in the spacers. Also tapped the hole for the eye bolt.

Tonight I restaged the workshop by pulling down the rear spars from the shelves and several doubler and support brackets that are placed at key locations along the rear spar.  I have a lot of edge deburring and priming to do on these parts, so we'll see how long it takes me to get through all that next week. After the rear spars comes the main ribs, and then the fuel tanks.

Wings 36, Total 499 - Finishing up Left Tie Down Bracket

Had a really good all around aviation day yesterday. Volunteered at the Chapter YE Ralley yesterday morning, where we flew some 40-odd girl scouts and other kids. One of them was special, however. My friend and fellow builder had Mike Rettig (PPILOTMIKE on VAF) Submitted a post on VAF a while back to solicit some support for a young man with an interest in aviation that has a serious brain tumor. His name is Alex Cuellar and you can read about him here.

He is currently recovering from chemotherapy and the response from the VAF community has been overwhelming. He went up for a one hour flight yesterday in an RV-6A owned and piloted by Gary Zilik. Gary's response to me when they when I asked him how it went was "he really needed it." Now the effort is on to try to get this young man up to Airventure this year, God willing.

As for the build, I did manage to get about an hour in yesterday to finish up drilling nut plate holes through the tie down bracket and also tapping the hole for the 3/8 inch eye bolt that will be used to tie the aircraft down when a hangar is not otherwise available.

Here I am basically repeating the process of drilling the nut plate holes for the other spacer that I did not get a chance to finish due to the storms the other evening.

And repeating the same bolt-centering process through the holes

Then I had to make a decision about coutersinking the rivet holes. Since my countersink bit broke the other day, and the new one is still on order, I decided to try to finish the remaining holes by using the debur bit, similar to how I did them during the elevator spar construction. IN this next pic, you can see how close to the edge one of them ended up being. Not too happy about this. But the word from Vans and from other builds is that this is not uncommon, and the the load is being carried by the bolt, which is secured by the nut plate. So apparently this is not a concern, but it still bugs the hell out of me because on the other side of this assembly are the brackets that hold the aileron belcrank assembly in place. If anything fails in that assembly then it's "Katy bar the door."
 Apparently many are flying like this with no problems - so be it.

There were no problems countersinking the holes with the deburring bit. Here is the tie down bracket showing all nut plate holes drill and deburred:

And then finally came the tapping of the hole for the eye bolt. This was actually pretty fun. It has to be about the largest hole I have ever tapped. ONce I was certain that the tap was going in straight everything was pretty easy to do. Just put it in the vise with wood blocks on both sides, and tap-away. My only concern about this was that I have a chart with the tapping hole sizes that are required for difference size holes. I measured the hole diamter in the bracket as supplied by Vans, adn it seemed as though the hole diameter was a bit smaller than the published hole size in the chart. So I wasn't sure if I was supposed to drill out this hole a bit more first, or just start tapping it.

Since Vans did not mention anything about drilling the hole to proper size, and I knew that this is an area where strength is rather important, I decided not to mess with any more drilling, and went ahead and tapped the existing hole. You need to tap to a depth of 1 inch, AND the eye bolt needs to line up in line with the air stream of the aircraft when it gets tight. I used some 3 in 1 oil to help remove the debris as the tap went deeper into the hole, backing it out occassionaly to clean the tap and remove the cut aluminum slag. Took a few minutes, and came out just fine. Remember, use a 3/8 x 16 tap for this, NOT a 3.8 x 24. Some tap and Die sets come with both size taps, so beware!.

And the fnished hole:

Confirmed the depth by using a sharpee to mark the bolt.

And this one with the bolt inserted and in its proper position:

I will finish the bracket and spacer assembly for the right wing today, and will hold off priming the parts until I have completed some of the rear spar doublers and support brackets so that I have enough parts to prime all at once. My primer arrived the other day and I will get to try out my new spray gun as well.

Wings 35,Total 498 - Holy Tie Down Bracket Batman!

So I began the process of drilling the remaining 7 bolt holes through the tie down bracket and the spacers for the left wing spar tonight. Man what a process that was. I did decide to do it in a series of very carefully thought out steps to avoid messing up the spacers or the holes going into the tie down bracket, or worse yet,  screwing up the wing spar. I will attempt to cover the main steps to this process here, because you just can't find a lot of detailed info about how this gets done elsewhere. Hopefully it will benefit a future builder, and it will most certainly benefit me if I decide to build another one of these someday.

Everything was going great until the pilot on my #40 countersink bit broke while countersinking the rivet holes for the nut plates in the back side of the spacer. I was wondering when/if this might happen after experiencing several ocassions where inserting the pilot through a freshly drilled # 40 hole sure seemed awful tight. Either I torqued on the bit causing it to snap, or the base of the pilot had worn a groove in it from rubbing against an undersized hole over and over again, to the point where it could take it no more. It almost buggered up the countersunk hole beyond repair, but I think I can still salvage it. I had to use a 3/32 inch punch to get it out of the rivet hole, and that went OK.

Step one
Drill the bolt holes through each spacer, without the tie down bracket. Had to align them according to the plans, flush with the outer edges of the top and bottom spar bars:

Step 2
Using my large metal clamps and two pieces of wood, one on top and the other underneath to prevent damaging the metal with the clamp heads, I clamped the spacers in place tightly so they would not move while drilling the holes.

Step 3
You will do this a million times - turn the spar over and drill through the first hole, then put a 3/16 inch (gold) cleco through the spar web and the spacer hole to hold it in place. Repeat for the 3 remaining holes (2 per spacer).

Notice in this pic how the 1/2 wood block I am using completely cover the holes on the opposite side. I took care of this later by taking a thin strip of left over 3/4 inch plywood and cutting two very skinny clamping blocks on my band saw. I also cut them just a bit longer so they would fit the inside width of the spar almost from flange to flange.

Next pic shows the relative position of the nut plate after drilling the first hole. Note how close to the edges everything is. Precision is needed here to avoid messing things up.  IN reality, as long as you clamp everything in the proper position securely, drilling the holes goes pretty smoothly.

Step 4
Once the two holes on one side are drilled and clecoed, reposition the clamping blocks as necessary to drill the other two holes on the opposite side. Clecoes will keep te spacers from moving out of position if you need to reposition the blocks. SHown in this next pic is one of the two freshly cut and much skinnier clamping blocks that I fabricated.

Some of the rivet holes may end up very close to the edge. When drilling, go slowly and ensure that you are drilling as straight as possible (something that apprently is almost impossible for me to do when drilling through thick material for some reason.

Remember to click on the pics for larger more detailed image.

And another pci showing both of my clamping blocks. The trick to this is ensuring that the blocks run straight across from one end to the other. Took me a few tries to get the hang of how to place the blocks, using a combination of inserting clecoes or bolts on one side or the other as holes were drilled to keep the parts from moving during clamping. I only ad one problem using these blocks during the tie down bracket drilling, but I used a skinnier piece of particle board which worked out fine.

Step 5
Debure the holes in the spar web and the spacers, and label the spacers so you know which one goes where

Not very impressed with the holes in the spar web - slightly enlarged a couple of them. Not concerned about this because they are sandwiched between several layers of other parts that are secured to the spar web, but sure wish these looked a little better. Spacer holes looked OK - go figure.

Step 6
Now it's time to drill the remaining holes in the tie down bracket. The trick here is to align the spacers so that the holes will be properly match drilled through the tie down bracket. You cannot use clecoes in the spacers as this will interfere with the tie down bracket. First, however, you focus on the bracket attach holes on the outside edges, which do not require any spacer alignment. Do these first.

I needed to find something that was absolutely square to ensure that the bracket was square to the spar. I found the following trim molding ends that I had intended to use in the basement at one time, but never got around to finishing it up. These were about as square as anything I could find, and they fit almost perfectly in between the two spar bar bars. Sometimes you just have to use some imagination and use what's available. INsert the bolt in the first hole that was already drilled per the specs in the plans, and then square up the bracket.

The first hole I decided to drill with the bracket clamped in position was the one that is diagonal and opposite the one that was drilled initially. This provides some stability to the bracket by allowing you to insert bolts in the holes temporarily during all the clamping and flipping of the spar that occurs during this process. You have to keep flipping the spar over because when you clamp everything you are on the front side of the spar, but to drill the holes you must turn the spar over to access the predrilled holes which are used to match drill the holes through the spacers and the bracket. Also note that this is where I had to use a skinnier piece of wood so that it would not interfere with my square block against the inside edge of the bracket. Worked out great. Keep clamping and drilling until all 4 of the bracket attach holes have been drilled.

Here is the opposite with the bracket attach holes ready to be drilled.

And a shot with the drill in position. I made sure it was straight in the hole before I actually drilled it!

Note how the ends of the bracket are short of the edges of both spar bars - this is according to specs. This whole business about ensuring that the tie down bracket is square to the spar has to do with the placement of the Eye bolt that will screw into the bottom of this bracket. Apparently if this is not square the eye bolt end up cockeyed and will not sit correctly with the wing skins that are applied later. Squared it as best I could. I am happy with it.

Step 7
 Looks like I missed a pic of this. Once the bracket attach bolt holes have been drilled, remove the bracket, grab the spacers that were drilled earlier, place in their proper positions, using a straight edge to ensure that they are aligned properly. Then carefully take the tie down bracket and place it over the spacers and the spar, being careful NOT to upset or move the spacers in any way. Then you need to carefully clamp one side of the bracket so that the spacer holes on the other side can be drilled. Make sure that your clamps are placed over the area where the spacers are located, and NOT on the ends of the tie down bracket. This will ensure that the spacers are clamped tightly between the spar and the bracket, and they will not move during drilling. I think the above pic shows this.

Step 8
Now for my little trick that I came up with. So after clamping everything in palce, how can you be really sure that the spacers are in the correct location. The answer is simple:

Turn the spar over to expose the holes in the spar web. Then take the bolts and insert them into the holes. Remember that the spacer holes have already been drilled, so the bolt should drop down into the hole of the spar as well as the hole in the spacer of everything is aligned correctly. If not, then reclamp the spacers and the brackets until this step is acheived. This is how you know that the spacers are aligned correctly.

Next, remove the bolts and drill the holes the rest of the way through the tie down brackets. Worked pretty slick, if I do say so myself.

Check the holes by inserting the bolts through each of them

Step 9
Remove the clamps and bolts and reposition the clamps to the other side of the bracket, and repeat the alignment and drilling process in step 8 for the other side.

Step 10

Whne all the holes are drilled, remove the bracket and the spacers from the spar, debur the remaining holes in all parts as needed. Now its time to drill the holes for the nut plate rivets. My solution was to place one of the spacers in its correct position behind the bracket, then take an AN3 bolt and a nut plate, and partially insert the bolt through the spacer, the tie down bracket, and hand tighten it into the nut plate. Neither 1/8 inch or 3/16 inch clecoes will secure the nut plate (either too small or too big), so you are left with clamping things into position once again. What a pain. The next pic shows how I did it with some small bar clamps  these worked quite well. I thought I had positions the nut plates relativey vertically, but as my next pics will show, it wasn't perfect. So much for eyeballing it!. This is not important as long as the nut plates can still be securely fastened to the spacer and the tie down bracket. Also remember that you are NOT riveting this assembly to the Wing spar. This is by design so that you can remove the tie down bracket and replace the nut plates if necessary after the plane is flying.

This is important because these nut plates will be securing the bolts that hold the aileron belcrank bracket in place. So if these start to come loose, that could be a very bad day indeed.

Next is how I set up everything to drill the #40 rivet holes, using the nut plate holes as a drill guide:

Once one side the nut plate rivet holes are drilled, clecoes can hold the assembly in place so that the holes on the other side can be drilled. Once this is done, remove the spacers and nut plates from the tie down bracket, debur the rivet holes,and prep them for countersinking on the back side of the spacer. I shoujld also point out that I used additional spacers under the tie down bracket to help stabilize it on the drill board while I was drilling the rivet holes for the nut plates. The problem with countersinking the rivet holes is that you are right on the edge of the spacer, adn the countersink cage has no real estate to rest on to stabilize the tool while countersinking the hole. My solution again was to use additional spacers by butting them up against each other to create an even platform of metal that is now large enough to support the circumferance of the countersink cage. This was working just fine right up to the point where my countersink pilot broke off while doing the first hole.

Then the thunder boomers showed up so it was a quick dash to clear the shop and put the cars in the garage before they got hailed on. SO I need to order a new #40 countersink bit and still need to tap the bottom of the tie down bracket for the eye bolt, which takes a 3/8 x 16 tap. Then, once that is all done, I need to repeat this same 10 step process for the right wing tie down bracket and spacers. Then its prep for primer, prime, and bolt it all together.

How's that for two hours worth of work? I don't know how others drill the holes for these things, but I suspect a lot of folks are clamping the hole shebang together and drilling through everything. I just did not like that approach very much because there is too much room for error or mis-aligned holes. I like the way that I broke this down to a series of sub-steps that ensures that all the holes are where they are supposed to be, and all the parts are lined up correctly as well.

Till tomorrow, KPR.

Lions and Tie Downs and Spacers - OOH MY!

OK, as promised, pics from the last two days of activty.

First is shot with the lightening holes drilled out of the spacers, nut place placed on top temporarily, and spacers placed in position to show where they are located on the Wing spar, The sapcers get nuzzled up against the inner edges of the top and bottom Spar bars, and the tie down bracket goes over the top of this. 8 holes per tie down to drill, plus the additional rivet holes for each of the nut plates.

Next pic is a bit blurry, bt I took this to show how precise you need to be when driling these buggers on the edges of the spacers. The spacer will cover the two holes just to the right of it in this sideways pic, and you can see how close to the edges of the spacer each of these holes will be. This means that they need to be clamped securely in place and kept in place during the drilling process.

Next is my process for drilling out the large lightening holes in each of the spacers. I first cut each spacer to rough size - 1.25 x 2 inches per the plans. Used my band saw and a scrap piece of wood to catch the metal shavings before they can travel through the saw wheels and guides - worked great. That was the easy part. Next came the hole saw rig. Here is the drill press with the two angles clamped into position with the 1 inch hole saw in the chuck. I took one of the spacers and slid it in between each of the angles, then adjusted my drill press table and vise to center up the drill arbor on the punched hole in the spacer that I had already measured per the plans. I needed about 8 hands to set this up easily. I guess after doing all this I read some posts tonight where people have been using the unibit for this, but I ahve also heard of folks having problems with that approach, which is why I opted for the hole saw approach. I wanted to be sure I was safe from any flying metal should the worst happen, so C clamps instead of bar clamps were the order of the day for this little feat.

And another blurry pic that shows a spacer inserted in between the angles. This was to keep the spacer from being able to shoot out should the hole saw end up grabbing the metal and torqueing it over hard for some reason. Worked pretty well but was a pain in the ass to get clamped up correctly. The spacer in this pic is already drilled and is not in the actual position for drilling, but you get the idea. Notice all the shavings too. Made a huge mess in the shop.

Safety glasses or goggles are a must for this:

Once the spacers were drilled, you end up with some interesting by-products:

Now on to the bolt holes for the tie down brackets. The plan tell you to measure and mark the hole for the top outboard hole, adn drill that one first. I also did these fitst holes on the drill press, and yes, clamping these brackets was a bit of challenge due to their odd shape.

And the hole after drilling:

Then you fit it on the spar by placing one of the bolts through the hole and align the tie down bracket so it is square with the spar. The edge of the bracket actually overhanges the ends of the spar bars by about 1/8 of an inch. This is clearly shown in the plans, but why it ends up this way is a mystery to me. The ends of the tie down brackets will also be just short of the edges of both spar bars. This is also shown on the plans:

Forgot to mention that I deburred all the spacers after drilling the lightening holes. This last pic shows how the spacers will be underneath the tie down bracket (shown off to the side in this pic for orientation).

Vans tells you to clamp everything in place adn back drill the 7 remaining bolt holes in each bracket/spacer. So this evening I spent considerable time trying to figure out how best to do this. I have some large metal clamps that have just been waiting for the right opportunity to be used, and this seemed like the right time. Anyway, long story short, and I'm too tired to go get a pic of this madness, I finally had an epiphony after struggling with the clamping process to make this all work. Instead of trying to clamp the sapcers AND the bracket together adn drilling through everything, I finally realized that I can just position the spacers and clamp them down and drill the holes through them first -  or maybe not. Guess I am tired enough that I just need to stop until I can figure this out and move on. Can't find details on other build sites or VAF that elaborate on how this was done. SO looks like clamping and drilling will take place tomorrow, assuming I figure out the easy way to do this.

Wings 33, Total 496 - Fabricating Tie Down Bracket Spacers

Last night I had the dubious pleasure of attempting to drill a really big 1 inch diamter hole smack in the middle of a 1.25 x 2 inch rectangular piece of 1/4 inch thick extruded aluminum bar stock - a total of 4 times. Gee, where to begin. I have a ton of pics that I will post tomorrow - too tired to deal with it tonight.

I purchased a 1 inch diameter hole saw and mandrel from HD - smallest one I already had in my possession was 1.25 inches, so had to buy one. If you do the math you end up with a lightening hole that leaves about 1/8 of an inch on 2 sides of the spacer, and about 1/2 inch on each of the other 2 sides. Those are the critical sides because you have to leave enough material to drill the nut plate holes for an AN 3 bolt on either side of the spacer.

Since I was going to be driling a rather large hole in a rather small piece of thick aluminum, this was a job to be done on the drill press. I spent an enormous amount of time trying to igure out how best to clamp this thing to my table top so I could hit the mark dead center and prevent any wondering of the blades on the hole saw. I ended up using those 3 foot long pieces of aluminum angle that I used to countersink all the nut plates as a fence to hold the spacer in place. What a pain in the ass it was to get everything clamped up right, but I finally got it there.

Then I began the drilling. The pilot bit (1/4 inch) went in with no problem. Once the hole saw blades hit the spacer - different story. The cutting blades were heating up so badlly that the aluminum shavings were melting an filling the gaps between the hole saw blade tips. I had to stop, clean, oil, and drill the hole several times before I finally broke through the 1/4 inch thick spacer. Now, can you guess what I did wrong? More on that in a moment.

I managed to get all 4 spacer holes drilled out to the correct dimension and location, and made a mess of my basement floor, work bench, and everything within a 4 foot radius of the press. Metal shavings went everywhere. After spending a good 1/2 hour tonight cleaning up the mess, and thinking about why I had such a hard time drilling them out with the hole saw, it suddenly dawned on me. A quick reference to my drill press manual revealed a chart that contained drill speed settings based on drill bit size and material type.

Sure enough, and the drill bit size got larger the bit speed got - you guessed it SLOWER. My drill press set up for "as fast as possible," and did not give a second thought to changing the speed by adjusting my belts, since my last use of the press to drill the lead counterweights for the elevators seemed to go OK at the higher speed. Problem was that the lead counterweights were drilled with a MUCH smaller drill bit. In other words, with a 1 inch wide hole saw, I needed to take the press down to the slowest speed I could possibly get, and I never did that. So, future builders - if you hit this step, make sure you slow down the drill press before you start burrowing large holes into thick aluminum. Seeing smoke rising from the metal within seconds of beginning the cut, even after heavily oiling it, should have been enough to give me a clue as to what was needed to resolve the problem.

Oh well, "live and learn" is just part of the process of building an airplane. After spending most of my evening tonight cleaning up my mess from last night, I also managed to clamp and drill the first of several holes in each tie down bracket. The process is basically to mark and drill only one hole in each bracket initially. This is the outermost hole on the top side of each bracket. The remaining holes are drilled by using the predrilled bolt holes in the wing spar. So as long as you get the first one correct, and you clamp the spacers in the correct location, drilling the remaining bolt holes should go fairly quickly.

What may trip up some folks is that they only show you the left side bracket. You have to be intelligent enough to figure out that you need to reverse the pictures when working on parts for the other wing, or you may end up with 2 left wings! So far I am keeping up with this, but it is difficult sometimes, because the wing part of this project has you constantly switching between about 6 different plan views for one thing or another. Sometimes you have to work hard to retain a sense of right vs. left before cutting or drilling something.

So far so good. Pics and more progress tomorrow for certain. Also expecting my Nobel Akzo primer to arrive from Aircraft Spruce tomorrow. Then I get to play with my new larger capacity spray gun!

Wings 30,Total 493 - Wing Tie Down Brackets

I managed to crank out a few more things before calling it quits for the weekend. I needed to slightly trim the two wing tie down bracket extrusions to match the length specified in the plans. Used my sander for the rough trim, followed by the scotch brite wheel. I was a bit surprised to see that aluminum is being used for these parts instead of steel. I then needed to cut 4 spacers from the provided bar stock using the band saw. Each of these spacers requires a 1 inch diameter lightening hole, as well as the necessary holes on either side of that for the nut plates that will secure the bolts for the aileron bellcranks.

I find this to be a rather fascinating part of the build, because the wing tie down brackets are also an integral part of the process to secure the aileron belcranks. The tie down brackets go on the front face of the wing spar, while the aileron belcranks mount to the back side. 

To finish up I need to drill all the mounting holes and tap the hole to make te threads for the 3/8 inch tie down ring. It takes a 3/8 x 16 tap, and I also bought two standard 3/8 inch eye bolts from HD to use as test bolts during the build. I already have the necessary tap, so I should be able to get those done in relatively short order. I will use a 1 inch hole saw in the drill press for the lightening holes in each of the spacers.

Lastly, I had to do some searching for the necessary hardware. Turns out I probably need another set of organizer drawers to further separate and label some of the wing hardware. I combined some of it by the way that it was originally bagged up by Vans, but now I am finding that to be a bit confusing as I search for specific hardware called out in the plans. It is easier if every specific type and size of hardware is separated and in its own compartment.

Wings 29, Total 492 - RIght Spar nut plates done

One major difference between the right and left spars was that I did not like the countersunk depth of the rivets after I had applied the primer, so I basically ended up adjusting the countersink tool and going over each rivet hole on the right spar one more time. What a pain - literally.

I had a ton of stuff going last week so it has been a few days since I have been able to post. I had to get past a milestone birthday, and also got to go to the show Wicked on Friday night, which was fun. Yesterday was a day for oil - changing it in the cars and in my compressor, as well as the lawn mower. Spring is here in Colorado. I did manage to squeek out a little time last night to start setting the 2 additional AN4 bolt nut plates that go on the inboard sections of both spars. Thes nut plates hold additional bolts that are used for attaching the wing spars to the center center of the spar that travels through the fuselage. I had to countersink the rivet holes for these as well, add primer, and readjust the hand squeezer depth to account do the the added thickness of the spar web and the support plate.

One note about this which I added to a post on VAF talking about similar concerns about poorly written plans. Vans mentions that the drawing that contains the refences for these additional nut plates is DWG 11A. I searched and searched my large plan set looking for this particular drawing, because I needed to find the rivet call out for these additional nut plates. But, no DWG 11A was in my set of plans. Then, after thinking about it for a second, I realized that the DWG 11A drawing is not included with the Wing Kit because the center section for the RV8 is delivered with the Fuselage kit, and NOT the wing kit. The RV7 includes the center section with the wing kit I guess, but not for the RV 8. Therefore, I had to resort to the drawing in my preview plans to locate the rivets for the additional nut plates, which are AN426AD3-6 rivets. This is perhaps the longest AN426 rivet I had set to date, but there are many more that are even longer that are yet to come. THe rivet needs to be so long to get through the thickness of all of the wing spar web material.

So here is a pic of the right wing spar tank nut plates completed:

This next pic are the series of inboard nut plates that are set at angles due to the additional ribs for the wing walk area that make space in this area a bit tight.

Next is the nut plate hole prep for the two AN4 bolt nut plates at the root of the spar. It is constantly aggravating to me that as you apply the microstop countersink tool to metal of different thicknesses or densities, you seem to have to make additional adjustments to the depth of the bit to obtain the right sized countersink. I do not know why this is the case, just that it is. I had to deepen my tool another 2 clicks or so to acheive the correct depth for the rivets. Then primed them just as I did on the other ones, and readjusted my hand squeezer depth to correctly set the rivets/nut plates.

Here is a blurry pic of the nut plates and the rivets used to attach them.

Here are the tapered tipped q tips that purchased to apply the primer to each of the countersunk holes:

Next came the solution to my boo boo on th left wing spar inspection plate nut plate holes. I was able to purchase the necessary triangle shaped MS21055-L06 nut plates from a local supplier just north east of Denver. THis pick is blurry as well - not sure why - but certain it is totally due to operator error.

The method I used to drill the two new rivet holes, which you have to do since the holes are located in completely different places due to the different shape of the nut plate, was to cleco the nut plate to the outside of the spar flange so that I could use the rivet holes in the nut plate as drill guides to drill the rivet holes through the spar flange. This was not as stright forward as it might seem, since you had to cleco the nut plate initially by using the center hole where the screw goes. the problem with this is that the hole is already countersunk for the screw and so you cannot automatically center the nut plate just by inserting the cleco (#40) through the screw hole.

 So I ended up putting a cleco through the screw hole in the nut plate right next to this one, which was already riveted in place and centered. This allowed me to determine where the center of the nut plate was by checking the height of the cleco that stuck up above the edge of the spar flange. Then I did the best I could to match that same dimension of the corner nut plate but moving it ever so slightly until it appeared to mirror the position of the other cleco, adn also appeared to be centered in the countersunk screw hole. Then I drilled the rivet holes, deburred them, and countersunk them for the rivets. then primed them and set the rivets.

I think for now I will leave the other holes as is. they will be covered by the inspection plate most of the time and out of sight, and there is no issue with leaving them that way. If I feel like it later on I may fill them with rivets to close them up, but this is not necessary. There are also no structural concerns about this, since this is one of about 20 or so nut plates that hold the inspection cover in place. After the nut plate was installed, the screw hole for the nut plate was centered in the hole almost exactly, so I was pleased with that. I am just happy I was able to find the right nut plates to fix the problem that I had created for myself when I did not pay attention to wich holes I was drilling at the time.

Next up is fabricating the Wing tie down brackets. Need to go find my tap and die set.