Bolts!

captain_john · Post by **captain_john** » Sun Feb 13, 2005 8:32 pm

Ok, time for me to dwell in minutia for a spell.

As you already know, I am waiting for some bolts. The package containing them is backordered.

What exactly am I waiting for? Are these 12 pointers the ones which I am expecting? Am I gonna get hexagonal ones like the one next to the drawing? What is the diff?

I see there are different styles, but how do they differ?

I have the Standard Handbook and am looking through it, but cannot extract the info I am looking for.

Also, what is the length measured in and from where to where?

I am expecting a certain fractional quantity and from under the head to the tip, but do not see a relationship.

I am sure it will be as plain as the nose on my face, but right now I am missing it.

Maybe I am getting tired?

Anyone?

CJ

captain_john · Post by **captain_john** » Sun Feb 13, 2005 8:51 pm

Oh yahhh... and just to muddy the waters, on plan 12A it shows a 6 point bolt in one detail and a 12 shear bolt in the other.

The more I look at this, the confuser I get!

CJ

arffguy · Post by **arffguy** » Sun Feb 13, 2005 8:55 pm

The drawings say AN3-7A. I am sure they will be regular hex head bolts. I have not seen 12 point tension head bolts on an RV yet. But now I will start looking for one. -7 is the length in 16ths I believe but of course I don't have my books with me right now either. By the way, I have three different aircraft standards books. Each has its strengths and weaknesses.

4kilo · Post by **4kilo** » Sun Feb 13, 2005 9:00 pm

CJ,

I can answer a couple of your questions, but not all.

The standard bolt you have shown in your photo is designed for mostly shear applications. Although it also has a fairly large amount of strength when loaded in tension, it is not nearly as strong in a tension application as the twelve point bolt on the drawing. That being said, the parts call-out on the drawing calls for a standard shear bolt. I am confused as well. Since the nut in the parts call-out is also not a tension nut, I would expect that the drawing is in error.

I don't remember what the fractions are in the bolt description, but I am pretty sure the length refers to the grip length and not the total length (you cannot measure from the bottom of the head to the end of bolt).

Pat

arffguy · Post by **arffguy** » Sun Feb 13, 2005 9:03 pm

By the way the RV-6 has a simpler way of mounting the tie-downs. It is held on with three simple AN3 bolts. And my plans don't even have a sheet named 12A. It goes 11, 12, 13 etc. What is your drawing 12A labeled as?

captain_john · Post by **captain_john** » Sun Feb 13, 2005 9:13 pm

Sorry Guys... my bad!

It is drawing 15A!

It's getting late.

Anyways, here is the "other" detail showing the Hexagonal's.

CJ

Terry B · Post by **Terry B** » Sun Feb 13, 2005 9:47 pm

... The length of AN aircraft bolts is measured from under the head to the end of the
shank. The "grip" is the unthreaded portion of the shank. ... Bolt Length, ...
www.aircraftspruce.com/catalog/hapages/anbolts2.php - 16k - -

Found the above on Aircraftspruce.com.

http://www.aircraftspruce.com/catalog/h ... gauges.php

The above link should show you a guage for measuring the size and length of bolts. On one end is different size slots. You place the bolt in the appropriate slot (diameter of the bolt) and then read the length of the bolt from the guage. The head of the bolt is not measured (only the shank as stated above.

Hope this is one thing you were asking.

Terry

I became intimately familure with the guages. Currently I am working on the top wing of a Fokker DR I Triplane and these guages really come in handy on restorations where you dont have all the hardware.

http://www.vintageaviation.org/aircraft ... index.html

Think there is a picture of the wings on this page. Two are covered and currently Im putting the hardware on the top wing so we can button it up as well.

arffguy · Post by **arffguy** » Sun Feb 13, 2005 11:07 pm

Yes. That's it. You are right about the bolt length gauges. I forgot about those.

I bet that the error on the plans showing the 12 point bolt heads probably came in when the drawing was made on the computer (by a human

)

That Fokker project is a good reality check. The next guy who whines to me about Van's parts and plans will be reminded of those types of things.

Luckily the technology is simple. (You ain't gonna put an IFR panel in it are you?

)

That's great that you are involved in such a project. Not just the plane but it looks like they got a lot of other work ahead of them there. I'm glad somebody has the energy and time to keep history alive. Good luck.

"Approach Experimental 6MF, we have that Fokker in sight."

captain_john · Post by **captain_john** » Mon Feb 14, 2005 6:44 am

Thanks for the 411 guys!

That is one nice Fokken project!

I will letcha know what bolts I am shipped.

Thanks again!

CJ

Dan A · Post by **Dan A** » Mon Feb 14, 2005 10:24 pm

CJ,
Okay I see a few links but no other information on the bolt lengths. So, here goes!

AN bolts are measured by 16th of an inch for the diameter like a #2 is a 1/8 in in dia, #3 is 3/16, #4 =1/4 and so forth. Length is measured by 1/8 th in. 2 thru 8 for the first inch then after that each inch is by the inch plus the 1/8 th measurement. A 1 1/4 in would be a #12. , a 1 3/4 in would be a #16 . So a bolt 1/4 in dia by 1 3/4 in length would be a AN 4-16 A 2 1/2 in length would be a 24, etc..etc..etc..! The new system (MS) is totlally different and I still haven't figured it out. But at least most suppliers still use the AN designation. Hope this helps!!
Dan

captain_john · Post by **captain_john** » Mon Feb 14, 2005 10:32 pm

Dan A wrote:Length is measured by 1/8 th in. 2 thru 8 for the first inch then after that each inch is by the inch plus the 1/8 th measurement. A 1 1/4 in would be a #12.

It does help. Probem is... it makes no fricken sense to me! Why would they do that? It is stoopid!

It sure would explain my eratic and questionable results when I was measuring a known -21A bolt!

CJ

Wicked Stick · Post by **Wicked Stick** » Tue Feb 15, 2005 12:52 am

Captain_John wrote:
Dan A wrote:Length is measured by 1/8 th in. 2 thru 8 for the first inch then after that each inch is by the inch plus the 1/8 th measurement. A 1 1/4 in would be a #12.
It does help. Probem is... it makes no fricken sense to me! Why would they do that? It is stoopid!

It sure would explain my eratic and questionable results when I was measuring a known -21A bolt!

CJ

John,
I can let you have one of my bolt guages if you want.

captain_john · Post by **captain_john** » Tue Feb 15, 2005 7:40 am

WS, I am catching on now. I think that just looking at it and measuring a few bolts up would be a help.

See you Wednesday night.

CJ