S

smiller

Well Known Member
Patron
Well this is my first post in these forums so I'll start off by introducing myself. I started construction of an RV-7A a couple months ago in a dilapidated outbuilding -- half of it with no floor at all (just gravel) and the rest of it with a wobbly uneven wooden floor. Eventually I hope to be able to persuade my wife to let me move into the garage but for now this outbuilding will have to do.

I'm by no means a handyman, have no prior experience and before this project had essentially no tools other than a hammer, pliers, and a couple of screwdrivers. But the salesman at Van's said, "No problem." :D

I haven't updated my blog in a while but you can read more about my project there.

Now for my problem: I'm currently working on the horizontal stabilizer (drawing 3). Per p. 6-3 of the instructions, I cleco'd/clamped the ribs HS-404, HS-405, HS-702 front spar, and HS-710 and HS-714 reinforcement angles and made sure all were pulled up tight. I don't have an angle drill so I used a 6" drill bit (the instructions say an angle drill is preferred "but a long drill will also work").

The problem is I couldn't drill those holes perpendicular to the materials. Two of the holes are through relatively thin aluminum and I'm not too worried (should I be?). The other two include the reinforcement angles and as a result the rivets are going to be crooked.

I've done only the left side only so far. I'm terrified to proceed and am not sure how best to do the right side (ugh, buy an angle drill?).

Here are pictures. Click on them for larger views. For the photos I've removed the nose rib HS-404 and just pushed a rivet into the hole so you can better see what I'm talking about.




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Advice appreciated, not only how to deal with the crooked holes I've already drilled, but how best to proceed on the right side (preferably without having to buy an angle drill, but I will if I have to).

--Shannon Miller
RV-7A Emp.
 
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Welcome to the forum!

Not sure how to deal with what you've got, but for future reference, you can also get 12 inch drill bits.

What sort of drill motor are you using? My air drill is very compact but my cordless electric drill is much bulkier (the chuck has a much larger outer diameter). I was able to drill mine using the air drill and a 12 inch bit and it came out perpendicular (if it was angled, it wasn't noticeable). I think the longer bit combined with a drill motor that can get pretty close to the rib makes a lot of difference.

I have since used my angle attachment several times and found it very nice to have too. If you're like many of us, you'll buy a whole lot of tools as you go through the build process....
 
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don't need an angle drill

Use a long bit as the post above stated. You can bend the bit in the middle by pushing it closer to the rib with a couple of your fingers. The bit will spin very well between your fingers with no problem, or use a glove if you must. The one rivet does look a little too crooked for my taste. You could drill it out to fit a 5/32 rivet if you have the appropriate rivet sets

steve ciha
 
Very repairable...

Shannon,

That crooked hole can be easily fixed, but I think the larger concern here is the lack of proper tools in the first place. You are going to need a right angle drill motor, now and for the rest of the project. Its use will come into play countless times over the course of the project. Unless your budget does not allow, I don't recommend investing in one of those cheap right angle adapters you chuck into a regular drill motor. Get a real right angle drill motor. I even use a 45 degree drill motor and is my favorite 75% of the time, but a right angle drill IS an essential tool in aircraft construction. Unless you are unusually gifted, you simply cannot do quality work without dedicated tools.

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Getting back to that crooked hole....it IS easily fixed but only with the proper tools and tooling to do a quality repair. It will require that the hole to be brought up to .161 and an AD5 rivet installed. Unless you have the proper tooling available...which I tend to doubt...do the following. Using a drill press to help assure perpendicularity, drill a #20 hole through a thick block of flat stock...steel would be the ideal medium but aluminum stock will suffice to repair this one hole. Cut the stock in such a way that it is large enough so it can be firmly clamped in at least two places over the surface of that crooked hole. This is your guide bushing...the tooling required to repair that hole. Here is a link to a tip that will give you a broad overview of the basics required to properly straighten (or move) any hole: http://www.vansairforce.com/community/showthread.php?t=11769

Welcome to the fascinating world of aircraft sheet metal work...your personal journey is only now just beginning! Have fun.
 
A long bit will work

Relax. You don't need every tool in the Avery catalog. I built my 6A without ever buying an angle drill. You can get by with long drill bits just fine. On the other hand, having the right tool sure makes things go easier. This 4 kit I'm building now came with all the other guy's tools, including a right-angle drill adapter and a full set of bits to go with it. What a luxury! It makes me wonder how I ever managed to build the 6A without one. But I STILL don't have a right-angle drill motor and don't see any reason to buy one (sorry, Rick).

You'll need a long 5/32 bit to fix the goof, and don't worry, there will be many more. Pick up a few long #30 and #40 bits while you're at it. Then instead of buying every conceivable size of #5 rivet, just get a bunch of AN470AD5-12's and a rivet cutter. And by the way, when ordering rivets be careful to order "AD" and not "A". The AD means it's heat treated. They will have a dimple in them. "A" rivets don't have a dimple and are too soft for aircraft construction. For some unknown reason, Spruce sells both and occasionally they'll send "A"'s when you ordered "AD"'s, so check for the dimple.
 
Thanks for all the help, guys. An order for some AD5 rivets is going out today, and I'm pondering the best way for me to go with regards to long bits, a bushing, angle adapters, or a full-fledged angle drill. Sounds like I can get by with long bits and possibly a bushing, but if I wanna be anal (and I sort of am in general) the angle drill is what I need. ;-) It's just that the first one I saw was $300. Ouch! I'll shop around. I'm leery of power tools from Harbor Freight, but maybe in this case???

A unanimous solution by all responders would be great, but I survived reading all the primer wars threads and somehow figured out the best primer solution for me. Haha. I'm glad folks here aren't afraid to disagree and argue pros and cons, actually!

Thanks again! Onwards and sideways...
 
New kits vs. old kits.

Jon... part of the question here might be how to drill holes with the newer pre-punched kits...:)

The old -6 and -4 kits you mention have no holes drilled in this area, so drilling a pilot hole in one side, and then using a long drill bit for the final #30 hole works well. This 12 inch drill bit process worked well in lots of locations on the -6.

I presume that with the newer kits that one side or other (the thinner spar web side, in this case?) is pre-punched, so the plan of drilling a way undersize pilot hole doesn't work...:)

If this assembly has one hole almost to size, then the techniques needed are quite different from the old kits.

Can anyone comment on the different techniques?

gil A

- bought 3 identical angles drills on E-bay for $110 - and they all work, yeah!


jonbakerok said:
Relax. You don't need every tool in the Avery catalog. I built my 6A without ever buying an angle drill. You can get by with long drill bits just fine. On the other hand, having the right tool sure makes things go easier. This 4 kit I'm building now came with all the other guy's tools, including a right-angle drill adapter and a full set of bits to go with it. What a luxury! It makes me wonder how I ever managed to build the 6A without one. But I STILL don't have a right-angle drill motor and don't see any reason to buy one (sorry, Rick).

You'll need a long 5/32 bit to fix the goof, and don't worry, there will be many more. Pick up a few long #30 and #40 bits while you're at it. Then instead of buying every conceivable size of #5 rivet, just get a bunch of AN470AD5-12's and a rivet cutter. And by the way, when ordering rivets be careful to order "AD" and not "A". The AD means it's heat treated. They will have a dimple in them. "A" rivets don't have a dimple and are too soft for aircraft construction. For some unknown reason, Spruce sells both and occasionally they'll send "A"'s when you ordered "AD"'s, so check for the dimple.
Click to expand...
 
Just FYI, my kit's new (purchased in October 2007) and most of the holes I've encountered so far are pre-punched, but not all, including the holes I'm talking about above. The instructions had me measure and mark for some "pilot holes" in the nose rib flange, drill them, then when all was cleco'd/clamped together with the other parts, to use those holes to drill through the whole assembly (it's that part where I couldn't get the bit perpendicular).
 
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Thanks for the clarification.... 12 inch bits...

smiller said:
Just FYI, my kit's new (purchased in October 2007) and most of the holes I've encountered so far are pre-punched, but not all, including the holes I'm talking about above. The instructions had me measure and mark for some "pilot holes" in the nose rib flange, drill them, then when all was cleco'd/clamped together with the other parts, to use those holes to drill through the whole assembly (it's that part where I couldn't get the bit perpendicular).
Click to expand...

Thanks for the clarification Shannon.

In the case you described, the use of 12 inch drill bits would be beneficial. Drill one side #40, clamp it all together tightly, drill #40 through both layers using the previously made pilot hole. Then drill #30 through both - which is quite easy with the #40 pilot hole.

If it's really difficult to get to, and you know that the #40 drill through with the 12 inch bit was square to the work, you can even take the assembly apart and enlarge the holes to #30 individually.

12 inch drill bits can be "flexed" in the #50 and #40 sizes if turned slowly in a cordless drill, and it is usually quite easy to set up the cutting end to be square to the work.

Another possible option is to use the 12 inch bit to just create a shallow "dimple" on the thick piece through your pilot hole, and then take the assembly apart and finish off the hole on a drill press, ensuring a hole square to the surface.

gil A

PS ... I like my angle drills, but they are harder to control accurately...
 
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I would also recommend a drill guide with a bushing set. I got an extra (long story short - I bought a set then found it cheaper elsewhere and was too late to cancel first order). I'd be willing to sell at cost of the cheaper set ($25, I bought it for $36 at skygeek http://www.skygeek.com/ats-dh01-kit.html).

Let me know.
 
"Official Answer"

A couple of you folks sent me private messages suggesting I talk to Van's about this, so I emailed them my post. They replied that the Douglas Aircraft Manufacturing book (I googled for this book but no luck) states that the maximum angle for a shop head is 8 degrees and 5 degrees for the manufactured head. Since mine is larger than that, they suggest I drill the hole again (straight this time!). They said I can go up to 9/64" if needed and still use an AD4 rivet, but if I must make the hole even larger to get it straight, I'll need to go to a 5/32" rivet (which is what I expect to do).

FYI. Thanks again for all your suggestions and offers.
 
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