240ZBUILTBYME 1971 240z HS-001063 Project Georgia

[Racer X]

6 minutes ago, 240ZBUILTBYME said:

Haha I’m not an engine guy so haven’t had to so far! 

I imagine you would have to move to fractions once working with engine component tolerances!  

I use decimals, it's easier.

At work we build airplanes to the nearest 1/1000th of an inch, but we express it as 0.001".

 

 

[240ZBUILTBYME]

Wow 😳 once you’re working at those sorts of tolerances you’re working in fractions/decimals anyway...

do you build the frame/body or the engines? I imagine the slightest variation in building the body/frame would alter the aircraft during flight. 

[dutchzcarguy]

11 hours ago, Racer X said:

You never measured out to 1/4 mm?

Hahaha... thats 0.25 mm overhere! 😉

10 hours ago, Racer X said:

At work we build airplanes to the nearest 1/1000th of an inch, but we express it as 0.001".

I have to react to this haha...  I once worked with studio equipment, still have some high quality stuff laying around and using some still after 34 years! (Look it up a revox b215 is one of those machines)  I was once at the factory in switserland and they make capstanshafts on a machine that measures 1/1000 of a millimeter! (For big taperecorders like the ReVox PR99, Studer A800 etc.etc.)  so 0,001 mm exact.  They make the shaft and then have to let it rest for a year in storage. Then after about  a year they put it in a machine that measures it and if it's out of tolerance ... it's scrap!

Her you see a machine made in switserland (Possible also in Germany (Studer revox still in Germany activ.)) The capstan is a shaft that gives the speed to a tape, it's that dark shaft just peaking out on top of the beige pressureroller. A recorder like this is as big as a jukebox and costed a million swiss franks and thats about $600.000,- This was in the 1980's.. today they are much cheaper..

Edited March 29, 2021 by dutchzcarguy

[Racer X]

19 hours ago, 240ZBUILTBYME said:

Wow 😳 once you’re working at those sorts of tolerances you’re working in fractions/decimals anyway...

do you build the frame/body or the engines? I imagine the slightest variation in building the body/frame would alter the aircraft during flight. 

I am a structures mechanic. Anything that is part of the airframe is what I (we) work on. As aerospace machinists our job is to fit and assemble commercial jet airliners, freighters and tankers (for the military). So far I have been part of the manufacture of the Boeing 777 (wings and fuselage), 777X (fuselage), and the 767 freighter and its derivative the KC-46 tanker (fuselage).

The airplanes are assembled in huge jigs, we call them “the tool”. The 777 wing assembly jig is huge, 4 stories tall, with a footprint larger than an American football field. 4 pairs of wings are assembled simultaneously. So the machinists are working “in the tool”.

The wing spars are also assembled in a tool, about 60 feet wide and 120 feet long. 
 

The 767, 747 body sections are assembled into larger sub assemblies in large 4 story high tools, similar to the wing assembly tools. The legacy 777 (metal wings) was assembled in a similar tool, which was removed and replaced by crawlers for a “moving” assembly line to also build the 777X.

After the wings and fuselage sections are complete they get joined at wing/body join, then final body join. 
 

At each step the various pieces are loaded into the tooling, positioned using indexes and checked with lasers to the nearest 0.001”.

Still, when an airplane is complete, due to manufacturing tolerances, each one is different in length.

I’ve read that a 747 can vary in length by as much as 18”.

 

So I suppose that none of them are perfectly straight, but all modern airplanes have provisions to trim, or adjust the airplane for straight and level flight.

 

 

The engines are manufactured elsewhere, and installed on the airplane by engine technicians who specialize in the hookup and installation of the engines.

 

Edited March 29, 2021 by Racer X

[ConVerTT]

Nice work Ryan!  Way to stick with it!
 

So i would cut out all the rust on the jig, fix the floor and rockers and then go to the rotisserie personally.  The jig holds everything straight.  I did each rocker and the front rails separately, but I am certain I could have cut more away at once. 

The floors basically attach to the trans tunnel and the inner rocker.  I had patched my inner rockers but once I got it on the jig I actually cut it all the way out and replaced it.  The frame didn't budge.  Same thing when I did the front rails.  
 

Have fun!!!!

Edited March 29, 2021 by ConVerTT

[240ZBUILTBYME]

On 3/30/2021 at 2:12 AM, Racer X said:

I am a structures mechanic. Anything that is part of the airframe is what I (we) work on. As aerospace machinists our job is to fit and assemble commercial jet airliners, freighters and tankers (for the military). So far I have been part of the manufacture of the Boeing 777 (wings and fuselage), 777X (fuselage), and the 767 freighter and its derivative the KC-46 tanker (fuselage).

 

Wow That is way too cool Mr X! no wonder you’re smarter than the average bear 🐻...

that’s crazy the variation in length considering the tolerance of the build, is that due to differences in temperatures, metal expanding etc I would think the hangar where you build would be temperature controlled to mitigate that? 

 

Edited April 1, 2021 by 240ZBUILTBYME

[Racer X]

36 minutes ago, 240ZBUILTBYME said:

Wow That is way too cool Mr X!

You can call me Racer.

 

36 minutes ago, 240ZBUILTBYME said:

 

no wonder you’re smarter than the average bear 🐻...

Aw, shucks, yer makin' me blush.

36 minutes ago, 240ZBUILTBYME said:

that’s crazy the variation in length considering the tolerance of the build, is that due to differences in temperatures, metal expanding etc I would think the hangar where you build would be temperature controlled to mitigate that? 

 

The variance comes from production tolerances, or the difference in size from one part to the next, for each of the thousands of parts that make the whole airplane. Production is carried out inside of buildings sheltered from weather. Although not all buildings are insulated with climate control, the heat generated from the manufacturing activities keeps them at a reasonably consistent temperature day by day. Also, some manufacturing environments are carried out in smaller, insulated and climate controlled buildings to prevent expansion or contraction of parts, such as wing spars, which are over 100 feet long, and could change in length a great deal even under only a small change in temperature.

So a 747-800 (the current model) is about 250 feet long. The fuselage is assembled from a few dozen exterior panel assemblies each made from a few hundred components (skin panels, frames, stringers), hundreds of floor beams and longitudinal beams, the longest being around 25 feet long. Also. when the bolts and rivets are installed, the metal around the holes is displaced, causing some deformation, and elongation, of the parts (this is accounted for in the engineering design). Although the size of the holes are always the same, there are still tolerances, and no two holes are exactly the same size. Additionally, the fasteners vary a bit in size. And when a rivet is driven, or a bolt tightened, again, no two are exactly the same.

So add up a few thousandths of an inch over 250 feet and all the many parts, and 18" isn't much.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

By the way, if you ever find yourself riding in a 747, go to the very last seat at the back, on an aisle. While the plane is taxiing, lean out and look towards the front of it. And during takeoff and flight, do it again.

Observe the floor.

It will twist, ripple, undulate, and curve up and down, so much so one might wonder how it can move this much and not break.

A similar thing can be observed while sitting at a window near the main wings, watching the tips rise and fall, and if one looks closely enough they can be seen to flutter or twist.

Relax, they are suppose to be flexible.

[240ZBUILTBYME]

After completing the chassis jig I decided to hold off on rust repairs until the car is blasted. The next step is to build my rotisserie. 

What I thought would be a relatively simple task turned out to be a nightmare. And upon trying to build the bumper mounts I realized my front end is a dog’s breakfast...

Now I knew the car had been in a front end collision but I didn’t realize it was this bad until I really started studying it. 

Notice the vertical panel kinks outward at the bottom where the front bumper mounts are, it should be straight up vertically, and flat. The radius of the bend should be round (roughly between 55mm radius rear bumper hole 40mm front hole). Mine is almost a 90 degree angle. 

so my dilemma was how to mount the rotisserie if my bumper mounts were more crooked than a politician. 

I used heat and a shrinking hammer to try and shrink the metal in the curved area and bring the radius back to pull the bumper mounts back into line. It worked reasonably well, to repair the area properly I will need to remove the bumper mount reinforcement panel where the jam nuts are. This is the after photo.

 

better but a long way to go to get to what it should look like... untainted photo below.

The same was done on the other side though the LHS is much worse. 

I wire wheeled the area to get a better look at the real damage, found some damage under some filler. 

when it had its collision the impact has sheared the areaaround the edge of the bumper mount reinforcement. 

LHS front of wheel arch is severely deformed. Air Ducting channel is crushed and misshapen. 

Area between wheel arch and radiator support has been pushed together, should be a much bigger gap. Rippling in sheet metal.

The more you look at it the worse it gets...

I am now contemplating transplanting the front nose of a untainted car onto mine due to the amount of damage that has been sustained. Anybody have any thoughts on this? As opposed to trying to pull everything out and repair it? 

Despite the significant blow to my morale I carried on and ended up starting the front mounts for the rotisserie.

I stuffed up and made the horizontal pieces too short.... they don’t clear the nose. What a fool. I had changed my design halfway through and did not account for the larger tube slipping over the vertical length.

I can make it work, but not ideal....

still so much to learn....

[Patcon]

My car has similar damage. I had it checked for being square and level on a frame rack. I dollied some of the wrinkled metal but its impossible to fix it all without removing the radiator support. In the end I dont care that much. I won't be able to see it from the drivers seat and it wont affect anything else

[240ZBUILTBYME]

5 hours ago, Patcon said:

I had it checked for being square and level on a frame rack

According to my rudimentary measurements my car is square, I have it on the leveled chassis jig and it is quite level.  Front radiator support is not level, I assume due to the damage, the strut towers are level though, which is the main thing. 

5 hours ago, Patcon said:

I won't be able to see it from the drivers seat and it wont affect anything else

I know you won’t see the damage but I feel like I feel like I’m going to go through so much to get the rest of the car right it would be a shame to not do the best repair possible.

I can either transplant the front section from a cleaner car, roughly from the front quarter of the wheel arch forward. Or I can repair the damage. Either way I’m removing the radiator support In my mind doing the transplant seems cleaner and simpler...

[ConVerTT]

Been there Ryan...

My thoughts - cut it out and replace it while you are still on the jig.  Check out my old thread - start from the bottom of page 5...

Look at the bright side...your metal fab skills are about to go through the roof 😉

https://www.classiczcars.com/forums/topic/61483-240z-fabbing-new-front-rails/?&page=5#comments

 

[Patcon]

One of my thoughts is good donors in Aussie might be hard to come by.

They're hard to come by where I'm at much less there...