Was destruction of SR-71-related tools really extraordinary? While reading about Lockheed SR-71 on Wikipedia I was baffled by a piece of information regarding Robert McNamara's order to destroy tools used to create Blackbirds, which took place in 1968 (at the beginning of SR-71's service), to prevent them from falling into anyone's hands.

While post-production cleanup of tools by planes manufacturers seems like a normal process (why waste space, resources, taxes, etc.), it appears that creation of any parts was impossible.
Although destruction of tools doesn't sound like a good idea to secure the technology (I somehow doubt the govt gave up on know-how and general knowledge - as for what can happen B-2's history can be a notable example), I'm still wondering:


Were all the tools indeed destroyed? If so, how were the planes maintained for all those years?
Were in said order any remarks regarding destruction of knowledge?
Why weren't the tools reconstructed after a few years?
That order sounds like a really bad idea - was there any legitimate reason for it?
was there any legitimate reason for it?

Unused tools, the tools for making a plane which isn't made anymore, are most probably put somewhere in storage, since the factory floor is best used for actual production.

While an aircraft plant for making top-notch, spyplanes is generally quite secure, any storage facility is probably less secured. Maintaining a high-security level for a storage facility seems like spending good money for a not awfully good purpose.

So in order to prevent the tools for the secret planes being stolen from a run-of-the-mill storage facility, it is much more secure to have them dismantled.

Note, that the SR-71 was produced in a time, where 24/7 surveilance was not as common as it is today. I suspect, that setting up a high-security storage facility would involve a lot of guards guarding basically junk-metal. Guarding scrap metal also doesn't seem to be an awfully motivating task for the guards.