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> with CNC and robots we can achieve far superior results for a fraction of the cost.

This is only true for mass production, where the set-up costs are spread across thousands of units. For small batches, the cost of automation often exceeds the cost of the batch itself. CNC machines are not magic; they require qualified and competent staff.

The same applies to quality control, fitting and assembly.

I don’t think they’re planning to start mass producing of SR-71s.

> because the job had become obsolete

You are greatly underestimating the number of parts, welds and inspections carried out on critical equipment that are done by hand or in small batches by highly skilled workers. The fact that they use a CNC machine does not make their job obsolete. In fact, quite the opposite is true, its require more skills.

Apart from the turbine section, virtually nothing on a helicopter is produced with a high level of automation or in large batch.

Still, I don't think anyone is ever going to hand assemble thousands of tubes for nozzle cooling & prepare them for brazing.

Not when you can get the same for a fraction of the cost by CNC milling the channels & then shrinking a jacket over it. Or in some cases even 3D printing the thing.

How does SpaceX's 3D printed raptor engine factor into your analysis?

The one that keeps failing?

Does it? SpaceX doesn't publish official numbers, but nextspaceflight.com has the Falcon 9 at 99.5% success rate, which seems a bit better than "keeps failing" to me.

https://nextspaceflight.com/rockets/3/

I actually agree with your point overall, but Falcon 9 uses the Merlin, not the newer raptor 3 for starship which is more 3d printing and has had some teething issues (no definite causation, and I expect they’ll get it sorted).

Falcon 9's don't fly raptors

The Raptor v3 had a 7% (3/39) failure rate on yesterday's Starship Flight 14. As others have mentioned, Falcon 9 uses the Merlin engine, which is a completely different, much lower complexity engine.

The assembly of the tube bundle in a nuclear steam generator is still carried out mainly by hand, using hundreds of shims, anti-vibration bars and supports.

At the other end of the spectrum are stamped-plate heat exchangers, which are mass-produced using a press line.

Each has its own specific application, and they are neither comparable nor interchangeable. The comparison makes no sense.

>> with CNC and robots we can achieve far superior results for a fraction of the cost.

> This is only true for mass production, where the set-up costs are spread across thousands of units. For small batches, the cost of automation often exceeds the cost of the batch itself. CNC machines are not magic; they require qualified and competent staff.

This isn't right.

CNC machines aren't magic and they do require skilled people to design for them and operate them.

BUT: they are an enormous advance on capability compared to 30 years ago and are absolutely not limited to mass production. 3D CNC milling is how most prototyping of metal parts is done and can be done to extraordinary precision, repeatably. It was always a low volume technology - it was Apple that started applying it in volume as part of mass manufacture.

While not metalwork, some are surprised to learn how old CNC machined guitars are. I have a Peavey T-60 and they were among the first CNC-machined production guitars in the late 1970s. It's going strong to this day as well, they're very well-built instruments.

Just to clarify one thing, Edwards AFB still has a lot of those highly-skilled engineers. Edwards has a huge machine shop with all the fancy tools and the engineers in there job is mostly making one-off replacement parts for planes. NASA and the Air Force are still flying all sorts of test planes out there and they often need some part they can no longer get from the manufacturer. They drop the spec for the part and it gets made, sometimes it takes a long time, but I promise there are skilled people on that base who can make it.
IMHO the SR-71 is going to be problematic due to sourcing the materials and fluids more than finding skilled CNC techs.

source: worked on Edwards for several years

No doubt there are highly skilled engineers there, but saying "those" might be a stretch. It is possible someone there has worked on an SR-71A, but it last flew 27 years ago. It was originally introduced 60 years ago. A lot of the knowledge about this plane has most likely unfortunately passed on. That isn't to say people can't learn, but it is a tougher starting point. Honestly, almost like starting over I would guess.

USAF has a lot of TOs (technical orders) that include things like schematics for the aircraft and its components. I'd be surprised if that data has disappeared or was incomplete for the SR-71. IME, TOs have been getting worse and systems from the time of the SR-71's period of service were generally better documented, though not perfectly.

> with CNC and robots we can achieve far superior results for a fraction of the cost

As far as I know that is still not true. Manual welding provides less defects and higher quality welds. Provided one has experienced welders. The cost is much lower for robotic welding but the results are still not as good as manual welding.

> Those skilled people retired (and by now died) without a replacement, because the job had become obsolete.

The skills can be acquired by new people.

Regardless I believe the industry has moved to 3d printed parts for engines due to lower costs, higher throughput. And in either case rigorous inspections are the way to get reliable parts.

I do agree that they cannot build a new F1, but they can build a new better model. But I believe that has to do with engineering and the loss of the contextual knowledge and experience building these things, the loss of why the design settled at what it did, why the processes settled to the ones documented, the undocumented knowledge the people building these had.

This knowledge can be rediscovered, but it would be easier/cheaper to start with a new design and acquire that knowledge organically.

> The skills can be acquired by new people.

They can be. However it will be expensive to train them. (starting with figuring out what training is needed - probably a lot of trial an error because not all of this was written down) Also you will need to pay people to get this training - they won't pay for it themselves since it is unlikely to be a useful job anywhere else anymore so they have better investments in their time/money.

> The skills can be acquired by new people.

I remember a Wall Street Journal article about 25 years ago where business leaders were upset that there was a "terrible" shortage of Swiss-style machinists in the US (whose daily output of tiny stuff would fit into a shot glass). And that they had to import those machinists from Germany.

Buried in the lede was that to get the skill level needed requires an apprenticeship that took at least 10 years. Germany provided that with trade schools and subsidies for hiring apprentices. In the US, the Cold War provided the money and incentive for aerospace and defense companies to subsidize that apprenticeship. High schools used to supply much of that trade education. I remember the high school that I was going to attend in NJ had vocational programs (for boys) in vending machine repair, machine shop and auto repair. Vocational education moved from high schools to community colleges. Along the way, community colleges went from free (for students) to something students have to pay for.

So the question becomes "who is going to pay for this?" I don't believe that what would be needed can possibly be done in America.

US corporations are allergic to paying for training in any form.

Everytime it’s come up people always argue that if you train the employee they’ll just leave for more money once they’re skilled.

Somehow just paying them the market rate so they stay, or even making a (shudders) contract with the employee to stay for X number of years in exchange for the training costs is never an option.

They’d rather have the position stay empty or outsource outside the country even if that has associated issues with shipping costs or quality control.

> Somehow just paying them the market rate so they stay

But your competitors can pay them more anyway, because they have not spend their money on training.

> a (shudders) contract with the employee to stay for X number of years

Literally shudders. Employer has no practical way to ensure adequate quality of work from their employee. Generally it is not a problem, because employer can get rid of those workers one way or another, but when you have spent money upfront... Shudders.

Thank you for reinforcing my point that no US corporation wants to pay for training.

> But your competitors can pay them more anyway, because they have not spend their money on training.

No, they spent their time without even having a partially trained employee and just having empty positions. If they are still outcompeting you, access to labor wasn’t your problem.

You can structure a contract so that the company has the right to fire for performance still. It’s how moving bonuses are normally done with a “you’ll work here for X year/s or return the bonus”

> The bigger problem there is that we don't have the people any more.

You don't have the education system and work ethic, stable family, curiosity. Many young people feel college is a waste and YouTube or AI has all the answers. Children in schools even now in 2026 right up to high school and even college can't read. Many who can read can't comprehend what they are reading.

In addition to that I recall a UK study that said smartphones have caused a lack of hand dexterity. Not social media or content but the phone itself a two dimensional surface means hand dexterity is not developed. People do not have hobbies like wood working, sewing, anything that involves fine manipulation and strength. The biggest hit is to the medical field and lack of surgeons because people in medical school now do not have fine motor skills needed for the job.

> You don't have the education system and work ethic, stable family, curiosity. Many young people feel college is a waste

I think a lot of this has been driven by businesses completely dropping their part of the deal in a pursuit of ever increasing profits. Formerly there was the long term promise that staying with one company would be rewarded and instead now for 99% of companies you're deeply punished if you don't hop jobs every couple years for a pay bump. Then they've also lobbied to completely gut funding for education to lower taxes or shift into subsidies. And a lot believe college is a waste because there's been a huge reduction in the value of just holding a college degree while the costs have ballooned.

The whole system that created it has been dismantled for profit long before the culture of it started to fall apart.

I’d suggest questioning the sources you are reading. Wood working and sewing are hugely popular hobbies across younger generations. There used to be a site, Ravelery.com maybe, that was on here all the time because of their engineering blog and all the work involved in sharing sewing patterns.

From what I recall it was specifically in the UK.

This maybe what I read.

https://www.bbc.com/news/education-46019429