Tightly fitted ancient Inca architecture
Just impeccable. Could you imagine cutting this back then? Let alone fitting it so perfectly? A technique or a few have definitely been lost.
I just wonder how it was cut. Like it must have been some kind of aggregate like sand and then some kind of hard(er) aggregate like sand?
I could imagine doing this with string. But the bevels?
Wiki suggests some chemical processes may have been involved
Additional surface smoothing near the edges of blocks has been attributed by some researchers to a chemical etching "mortar" composed of pyrite mining slurry and plants containing calcium oxalate.[31] Some species of bacteria from the genus Thiobacillus are able to process sulfidic minerals and produce sulfuric acid as a byproduct; complexation with oxalate increases the etching potential of the mixture. This would correspond with both contemporary descriptions of the Incan masonry process[31] and regional folklore suggesting that Incan masons and a local bird species, the pito, were capable of softening rocks with a local herb.[30]
One of my archaeology professors who focused on the Inca Empire bought into theories around using a kind of portable jig that allowed them to match surfaces similar in principle to how key cutters match the contours of a source key.
This was over a decade ago already so not sure where those theories line up.
That being said, the empire had INCREDIBLE engineering skill, and with a system of labour tax, I figure the proliferation of those skills would be great, and with such a broad base of the population exposed to engineering tasks I imagine there were many opportunities for diverse minds to contribute to process improvements
My sense is there would need to be some kind of mechanical assist to get things this both square, and flat. Two big flat rocks with an jig holding them and then you move the stones in a circular manner (like a oscillating sander but you move the piece not the aggregate).
Like just making a very flat surface is a surprising engineering feat, but I could imagine
I guess OPS picture really betrays how complex of stonework they could really put out. In OP's pic, they're uniform and square: not at all required to get the perfect fits that Inca masons are truely legendary for.
I mean, can you just imagine the sense of accomplishment you would get even doing one of these joins?
Also worth pointing out that Incan masonry didn't use mortar to join the bricks - they were cut so precise they didn't need it.
