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  #11  
Old 05-05-2022, 02:30 PM
dmuro2 dmuro2 is offline
 
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Default Countersinking the hinge ...

Quote:
Originally Posted by wirejock View Post
Excellent. You're correct and it's fabulous you are checking. However, for the toolbox, it won't be an issue. I would recommend countersinking the hinge. None of the hinges on an RV are dimpled. Tool box lid functions much better that way.
Sorry, had a couple of questions on the hinge …

First, I dimpled the box and lid before I did much research on the hinge and realized I should not have dimpled the box since I was going to countersink the flush rivets.

But when I went to countersink the hinge for the box, the eyelets are in the way of the countersink cage. They're even in the way of dimple dies if I wanted to dimple it. How the **** do you get in there? Is there a special cage, like a half cage I could buy, or would I need to cut it away, or grind my precious dimple dies? Or maybe I don't have the hinge on correctly and that's what's causing the issue?


The second question I had was around dimpling and what is a normal amount of distortion. I watched Paul Dye's video on setting up the squeezer for dimpling (leave enough room where the dies meet, but can twist), but after squeezing it looks like there's a bit of distortion on the metal. Is this normal? Would you back off a bit, or tighten up?

Funny how much I'm in the dark on this stuff and getting more nervous by the day about this build, lol.

Any help is appreciated, also if you see anything that could have been better, would appreciate a good critique. thank you!
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  #12  
Old 05-05-2022, 03:39 PM
MekMouse MekMouse is offline
 
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Location: Bonney Lake, Wa
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Quote:
Originally Posted by dmuro2 View Post



The second question I had was around dimpling and what is a normal amount of distortion. I watched Paul Dye's video on setting up the squeezer for dimpling (leave enough room where the dies meet, but can twist), but after squeezing it looks like there's a bit of distortion on the metal. Is this normal? Would you back off a bit, or tighten up?

Funny how much I'm in the dark on this stuff and getting more nervous by the day about this build, lol.
Paul's video from the Metal Magic series is pretty descriptive. another one that gets into the distortion is the dimple video from Cleveland Tools.

Don't worry to much about the angst your feeling right now. I felt the same while doing my first practice kit (I chose the control surface one) wasn't sure if I was doing it right or how to do some of the steps. but it went together.
then I followed Jason Ellis's advice and drilled out all the rivets and started over. Felt much better after take 2.

hopefully I'll remember those lessons when I get my first kit....next month???
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  #13  
Old 05-05-2022, 03:44 PM
wirejock's Avatar
wirejock wirejock is offline
 
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Location: Estes Park, CO
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Answers in red...

Quote:
Originally Posted by dmuro2 View Post
Sorry, had a couple of questions on the hinge …
Wow! First post. Official welcome will be along soon. Don't apologize. Now is the perfect time to make mistakes, ask and get help.

First, I dimpled the box and lid before I did much research on the hinge and realized I should not have dimpled the box since I was going to countersink the flush rivets.

Actually, you did it correctly. The rivets will be flush outside. You only need to countersink the hinge for the dimples. Nice when things fall into place! Technically, it's not the way Vans intended, but hinges on the airplane are rarely dimpled. They are usually countersinked. They distort when dimpled. You did it right.

But when I went to countersink the hinge for the box, the eyelets are in the way of the countersink cage. They're even in the way of dimple dies if I wanted to dimple it. How the **** do you get in there? Is there a special cage, like a half cage I could buy, or would I need to cut it away, or grind my precious dimple dies? Or maybe I don't have the hinge on correctly and that's what's causing the issue?

The toolbox hinge is smaller material than the airplane. It should be inside. Looks like you have one side of the hinge on the outside. The easiest way is to remove the cutter from the cage and countersink using a 1/4-28 extension on the drill press. Or put the cutter in a debur tool and do it manually. Also, most grind a flat on the female dimple dies to dimple tight spaces. You can also buy close quarter dies.

The second question I had was around dimpling and what is a normal amount of distortion. I watched Paul Dye's video on setting up the squeezer for dimpling (leave enough room where the dies meet, but can twist), but after squeezing it looks like there's a bit of distortion on the metal. Is this normal? Would you back off a bit, or tighten up?

The distortion is actually "under dimpling". If it's a manual squeezer, set the dies where they touch with no parts between when the squeezer is closed. The jaw will flex a tiny bit when a partbis dimpled. Tighten it up.

Funny how much I'm in the dark on this stuff and getting more nervous by the day about this build, lol.


I suggest finding a Mentor to help you start. A couple hours will answer a multitude of questions and avoid developing problematic processes.

Any help is appreciated, also if you see anything that could have been better, would appreciate a good critique. thank you!

Just under dimpling. Pretty hard to fix. You kinda need to get dimples right the first time. No worries. Buy some scrap and practice. Assemble the toolbox then drill it apart. Drilling out rivets is as important a skill as driving them. Thanks for the diversion. I had a bad day in the shop and it feels nice to help someone.
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Last edited by wirejock : 05-05-2022 at 05:18 PM.
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  #14  
Old 05-05-2022, 04:13 PM
DRMA DRMA is offline
 
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One other suggestion. If you are still uncertain or would like some 1-on-1 help, bring your tool box project to the next EAA 302 chapter meeting on May 14 (second Saturday of the month) held at the Galaxy FBO at Conroe airport. See EAA302.org for info on the chapter and directions to the meetings.

Get there a little early and ask someone for help. I'm sure you will find more than one member who will volunteer to help you at before and/or after the meeting. It's a great group of people, with many of the members building now or have built aircraft, including lots of RVs.

Welcome to the world of EAB!
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  #15  
Old 05-06-2022, 08:03 AM
Desert Rat Desert Rat is offline
 
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I see that wire jock has responded to the most recent post, and I know that the original poster's question about 2d minimum edge distance is a couple of years old at this point, but since this thread surfaced and I've got a few minutes, I'm going to try to answer it, because it comes up from time to time.

Usually, the (correct) short answer that somebody shoots back is just that the spec or engineering takes precedence over the 2d rule of thumb. However, as with most things in life, there is a hierarchy of what's acceptable and unacceptable, and it usually starts with "it depends". For airplanes, it usually looks like this;

1- Manufacturer's engineering data/publication
2- industry/government publication
3- rule of thumb.

The lowest rung on this hypothetical ladder is number 3. In reality, a rule of thumb isn't even its own category. It's just is a shortcut that keeps you out of trouble without having to run to the book to see what the actual rule from rung 2 is.

If you go up the ladder from "rule of thumb" to government publication", you get to a military specification or if there's not a specific mil-spec that covers your case, then you go to the industry bible, FAA Advisory Circular 43.13.

For rivets, the government publication we want is mil-spec MIL-R-47196A. Vans has been very helpful in linking this spec to their website under their support page, but it's been around in one form or another since some guys with sharp pencils and big brains figured all this out in the 1930's

In the case of 3/32 rivets, the 2d rule of thumb gives you 6/32 (.1875) from the center of the hole to the edge of the sheet. The "real" number from table VIII of the mil-spec is .156, which works out to be about 5/32. So we see that the rule of thumb that everybody knows, gives you 1/32" extra over what the real number is.

But wait...What about the top rung of the ladder? Those guys in the 1930's couldn't possibly foresee every possible exception right?

In all cases, option 1 above takes precedence over anything else because manufacturing drawings or instructions have been blessed by those mystical beings known as "Engineers" and tested/kit proofed by even more mystical beings with names like "The guys in Experimental," or "Static Test Dudes," or "Flight Test Pukes" and the whole process has as much or more hard data to back it up as the generic publications.

So, to sum up;

If Vans drawing says a hole should be dimension X, then that's where it goes. In most cases, they didn't re-invent the wheel, but just defaulted to an already existing rule from an already existing spec. If they deviated for some reason and have way more edge distance, or way less, they have a reason for doing what they're doing. More importantly, they wouldn't deviate from a known and proven engineering spec without having their own data that says in this particular instance, it's OK to do so.

If the manufacturer doesn't give specific guidance, then you default to known, proven guidance that has solid engineering to back it up. In the case of rivet holes, the 2d rule of thumb keeps you well within the guardrails of the mil-spec, but if you need to eat into that margin, you should crack open a book to see the minimum you're actually allowed.

Hope this helps.

Terry
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Last edited by Desert Rat : 05-06-2022 at 08:10 AM.
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  #16  
Old 05-06-2022, 11:51 AM
Taltruda Taltruda is offline
 
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Quote:
Originally Posted by Bruinpilot View Post
I just started working on the toolbox practice kit and have come to a standstill with the hinge. I know from studying 43-13 that I need at least 3 times he rivet diameter for edge spacing. So I need a minimum of 3/16 on the hinge edge. Unfortunately as I lay the thing out it seems like if I want the lid to close properly, I need to scoot the hing up a bit, and the. I can only achieve 5/32 edge spacing for the rivets. Is this a problem, or am I doing something wrong?
I believe the 3x thing is the rivet diameter should be 3x the thickness of the thickest piece in the sandwich? And edge distance is 2x (shooting from the hip here.) Sometimes 3x edge distance is specified because if you need to upsize to the next larger rivet, you’ll still have 2x edge distance.

I agree that you need to dimple harder to get that distortion to disappear.. you really can’t over dimple with a squeezer.
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  #17  
Old 05-06-2022, 01:47 PM
rocketman1988 rocketman1988 is offline
 
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Default …teaching

Another important thing the toolbox will teach is that perfection is the enemy of completion.

Set the bar as high as you want but always remember that there has never been and will never be a perfectly built airplane…

Realizing this during the toolbox build will help you when you make your first oops on the airplane.
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  #18  
Old 05-06-2022, 02:23 PM
David Paule David Paule is online now
 
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Forget the 3X edge distance. For our planes it's 2X per Scott's post.

For the dimples, the ones in the photos aren't being squeezed enough. You can't over-squeeze them. If you're using a squeezer, adjust it for the max force. If you're using a C-frame, get a bigger hammer and hit it hard. I use a 2 lb. hammer and whack those things at arms length. Fun.

I've found that Cleaveland's deburring tool, this one, is handy for making countersinks. Check often with a rivet.

The -3 rivets are actually .098, not 3/32, just so you know.

Dave
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  #19  
Old 05-10-2022, 03:35 PM
dmuro2 dmuro2 is offline
 
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Default Thank you!

@wirejock Thank you for the warm welcome (sorry for the late reply) and thank you so much for your insights, really appreciate it. Glad my groping in the dark was a distraction that lifted an otherwise down day.

Everything you've mentioned makes sense, but I have some follow up questions:

Quote:
"The toolbox hinge is smaller material than the airplane. It should be inside."
I agree, looks much cleaner on the inside. I put it on the outside initially because it looked like that was the intention from the illustration in the instructions.

Quote:
You only need to countersink the hinge for the dimples.
When I countersunk the hinge and the hinge was on the inside of the dimpled lid, it didn't lay flat. It's pretty close to being knife-edged holes, so I didn't want to countersink any further. Is there a trick to that? Did I dimple too much?


I have a new hinge on the way, so I can experiment a bit with what I have.

Also, just got word that my Emp kit will be crated at the end of May! Ordered last July and it's finally about to start!

Thanks again!
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  #20  
Old 05-10-2022, 04:15 PM
wirejock's Avatar
wirejock wirejock is offline
 
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Default Tool box

Answers in line RED
Quote:
Originally Posted by dmuro2 View Post
<snip>...
When I countersunk the hinge and the hinge was on the inside of the dimpled lid, it didn't lay flat. It's pretty close to being knife-edged holes, so I didn't want to countersink any further. Is there a trick to that? Did I dimple too much?

I should have mentioned I don't assemble the tool box per Vans instructions. You are absolutely right. It just doesn't look right with 1/2 inside and 1/2 outside.
You can't dimple too much.
The hinge material used on the airplane is wider. Most is .040-.063. QDo the best you can with what you have. It's practice. You're asking and double checking all the right questions. Keep up the good work!


<snip>

Also, just got word that my Emp kit will be crated at the end of May! Ordered last July and it's finally about to start!

Congratulations. Wish I could see the smile!.

Thanks again!
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Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved (3,000+ hours)
Empennage, wings, fuse, finishing kit done. Working FWF
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.

Last edited by wirejock : 05-10-2022 at 04:29 PM.
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