Drexlerian nanotech

[Alphadon]

What I mean to point out here is that Drexler made no allowances for progressively larger manufacturing implements. This is the crux of the problem: molecular assembly is good for things like transistors, but bad for things like a block of steel. Molecular assembly MUST be integrated with macroscopic processes to be effective. Which is why in some cases, a reconfigurable manufacturing machine may be better than a traditional universal assembler, as it can do things like build said ruler without the added task of molecular synthesis.