Only works if the grip length is smaller than the thread length.
Hi-loc is not available at Aircraft Spruce. I didn't find a convenient source.
Hi-loc is not available at Aircraft Spruce. I didn't find a convenient source.
This how airbus wings attach to fuselage
- Thread starter Aviator168
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That's not a traditional Hi-shear with a collar. Not a Hi-loc either. Looks like a NAS bolt. I found some flush NAS bolts with long threads but none with hex head. The instructions for bolt fit in AC 43.13 are limited.
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Aviator168
Well-Known Member
I think you have to custom order them. Aside from the pin, you are going to need the nut too.
Dan Thomas
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- Sep 17, 2008
- Messages
- 5,923
The tolerances of ordinary bolts, including AN bolts, don't accommodate that. In measuring AN bolt diameters I've found as much as .002" variation. Industrial bolts are no better. Hi-Locks, close-tolerance AN bolts and NAS bolts are far more accurately made.
Here's a chart of tolerances for Grade 5 and 8 bolts. Look at the huge allowances:
Well, I don't have that Airbus or Boeing high tolerance tooling drill guide either. So what to do? I tried several reamers and without a perfect drill guide I can't get a nice sized hole.
I was thinking of taking one of the bolts and turning it .0005" undersize and using it as a crude finish reamer.
Old IA, ex AF mechanic died and his family had an auction. I bought a huge supply of Hi-Loc's ( thousands). Gave all of them to an old friend that is an IA in Ohio. I did keep a bag of about 20 rolls of pinking tape and a 90 deg air drill.
Angusnofangus
Well-Known Member
The Hi-Lok pictured in post #22 is a reduced head, flush, shear. nominal sized fastener. Note the emphasis on 'shear'. A flush head, nominal, tension Hi-Lok is HL-18. A tension Hi-Lok can be used in shear, but not the other way around. Also, one doesn't have to have a Hi-Lok collar. MS-21042 nut with an AN960 washer is totally acceptable, and sometimes the only option in places where you can't get a Hi-Lok collar on. If using a nut on a shear Hi-Lok, one must be careful to just snug it up, not torque it down.
I don't want a flush head. I want a hex head to hold it to turn the nut. Any hex bolt would work. The problem is I can't get the hole a close interference fit yet.
Found this from Wil Taylor on another forum:
WKTaylor (Aeronautics)7 Oct 04 18:22
Guys.. a little caution here...
There are typically (4) types of structural fastener installations... I'll submit the following definitions for these catagories...
close-reamed = .0005--0.0015 clearance [hole shall be slightly larger than max true* diameter of a bolt, but still defined by very tight tolerance]
transition fit (-)0.0008-to-(+)0.0008 [nominal hole size equal to true* fastener diameter, +/- a small tolerance]
light interfernce fit = (-)0.0005-to-(-)0.0015+ [hole size guarenteed to generate interference with fstnr shank]
high interfernce fit = (-)0.0015-to-(-)0.0045 [hole size guarenteed to generate significant interference with shank, and require significant effort to drive-in]
Here are rules of thumb I have learned the hard way...
Use clearance or transition fit for applications as follows:
A) where ANY of the base material(s) have an SCC [stress corrosion cracking] threshold below 25KSI in the ST orientation.
B) material stack-ups of aluminum thicker/deeper than +2Dia thickness [simply to assure high quality fastener installation W/O having to hammer/press fasteners into tight holes in deep structure [can damage holes and fastener heads!!]
C) for any stack-up that includes (any) layer(s) of steel, CRES or titanium.
Use light interference for most jobs in SCC resistant aluminum materials for trade-off on installation of good quality fastening and fatigue performance. Note: use of Hi-Loks is probably Ok in light interference... but Hi-Tigue style HL would generally be easier and less damaging to install. SOMETIMES this stack-up can include titanium... but I don't recommend it without careful study of installation forces!
For heavy interference only use Hi-Tigue style Hi-Loks (variation on Hi-Lok design for smooth fit during interference installations) in aluminum structure ONLY... after considerable study of potential fatigue-durability benefits VS risks of installation damage (may require extreme force to drive into position)... and potential for SCC in [usually] alloys/tempers.
Regards, Wil Taylor
* true fastener diameter as defined by the fastener [or mnfctrs] specification
Regards, Wil Taylor
WKTaylor (Aeronautics)7 Oct 04 18:22
Guys.. a little caution here...
There are typically (4) types of structural fastener installations... I'll submit the following definitions for these catagories...
close-reamed = .0005--0.0015 clearance [hole shall be slightly larger than max true* diameter of a bolt, but still defined by very tight tolerance]
transition fit (-)0.0008-to-(+)0.0008 [nominal hole size equal to true* fastener diameter, +/- a small tolerance]
light interfernce fit = (-)0.0005-to-(-)0.0015+ [hole size guarenteed to generate interference with fstnr shank]
high interfernce fit = (-)0.0015-to-(-)0.0045 [hole size guarenteed to generate significant interference with shank, and require significant effort to drive-in]
Here are rules of thumb I have learned the hard way...
Use clearance or transition fit for applications as follows:
A) where ANY of the base material(s) have an SCC [stress corrosion cracking] threshold below 25KSI in the ST orientation.
B) material stack-ups of aluminum thicker/deeper than +2Dia thickness [simply to assure high quality fastener installation W/O having to hammer/press fasteners into tight holes in deep structure [can damage holes and fastener heads!!]
C) for any stack-up that includes (any) layer(s) of steel, CRES or titanium.
Use light interference for most jobs in SCC resistant aluminum materials for trade-off on installation of good quality fastening and fatigue performance. Note: use of Hi-Loks is probably Ok in light interference... but Hi-Tigue style HL would generally be easier and less damaging to install. SOMETIMES this stack-up can include titanium... but I don't recommend it without careful study of installation forces!
For heavy interference only use Hi-Tigue style Hi-Loks (variation on Hi-Lok design for smooth fit during interference installations) in aluminum structure ONLY... after considerable study of potential fatigue-durability benefits VS risks of installation damage (may require extreme force to drive into position)... and potential for SCC in [usually] alloys/tempers.
Regards, Wil Taylor
* true fastener diameter as defined by the fastener [or mnfctrs] specification
Regards, Wil Taylor
Bringing this back home, apparently this is part of a series of episodes of a German children's education TV show called Der Sendung mit der maus ("The show with the mouse"). They follow the progress of Airbus A321 s/n 901 (Later Lufthansa D-AIRY) from raw material to finished aircraft, with some great process details. Worth watching, even if you don't sprechen sie deutsch. Here's a link to the 8-video YT playlist:
This appears to be the entire two-hour video:
Oh, and "Was ist ein D-Check:"
This appears to be the entire two-hour video:
Oh, and "Was ist ein D-Check:"
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flat6
Well-Known Member
Jigless assembly or fly away tooling. The wing attach points seem to have one pair of precision drilled hole. The others are smallish pilot holes. Temporary fasteners are then attached to the holes and final drilled in place. the wing loads are reacted with friction fit between the flanges. There are no jigs. Just simple precision jacks at a few reinforced places that look like kinematic joints.
TFF
Well-Known Member
If you are going to go for extreme tight tolerances, you will have to do them at a controlled temperature. Just handling the hardware can grow the piece and make it not fit. Each one of the bolts were matched to the fittings at the machine shop. Some may be standard and interchangeable, but some probably had to be custom ground or threaded, and it’s not a visual thing. The Guy Martin show where a Spitfire is restored has a good bit on its wing mount hardware.
Also, if the wing ever had to come off that Airbus, it’s a scrap plane. It is not a serviceable joint. When I worked at a regional airline, a pilot essentially ground looped one of the jets through a ditch just like a student would do with little experience. They rebuilt the plane at that out station. It was the first time that manufacturer had ever removed the wing from the fuselage, and it had serviceable wing mounts. It was a brand new plane and I’m sure insurance was not going to total it with so few hours. Those were easy to take the wing off though. It was held on by about eight struts that look like auto front drive dog bone engine mounts. Bearings with grease fittings.
Also, if the wing ever had to come off that Airbus, it’s a scrap plane. It is not a serviceable joint. When I worked at a regional airline, a pilot essentially ground looped one of the jets through a ditch just like a student would do with little experience. They rebuilt the plane at that out station. It was the first time that manufacturer had ever removed the wing from the fuselage, and it had serviceable wing mounts. It was a brand new plane and I’m sure insurance was not going to total it with so few hours. Those were easy to take the wing off though. It was held on by about eight struts that look like auto front drive dog bone engine mounts. Bearings with grease fittings.
trimtab
Well-Known Member
Billski hit the rivet in the head with his description of rivet joint mechanics.
The joint between the inboard and outboard spar cap sections of the HP-18 is similar to this. A diamond shaped splice plate joins the two, with 12 NAS4703 screws in each cap section for a total of 24 screws per cap, 48 per spar, 96 per wingset. You carefully drill up to #13, which produces a light drive fit on the #10 screw shank. Then you drive each screw in with a hammer or rivet gun, just like in the Maus video, and pull it home with an AN365 nut.
David L. Downey
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- Aug 7, 2019
- Messages
- 102
have not seen this mentioned on this thread (might have missed it?). A 2 flute drill bit generates a 3 sided hole. The use of "double margin" drill bits allows for a much more circular hole, and a cleaner hole closer to the designed diameter. I also find that the burrs are reduced in aluminum drilling when using them.
TFF
Well-Known Member
Here is the segment of the Guy Martin video. Wing bolt is in the middle.
Boeing also uses drive fit and nuts, not Hi-loc, according to my friend.
Angusnofangus
Well-Known Member
I don't know what a drive fit is, but I've done a lot of structural work on 727's and 737's, and there was lots of original Hi-Loks, also Huck bolts. Maybe that is what your friend is referring to.
