“Gauge blocks are crafted to be so ultraflat and smooth that they stick together when placed against each other. They can only be parted by “wringing” – slide-twisting – them apart. Thus, when stacked, the sum of the amounts on each stacked block is accurate within a millionth of an inch.”
@snarfed.org if you haven’t seen it yet, Adam Savage nerding out over gauge blocks and the philosophy of measurement: https://m.youtube.com/watch?v=qE7dYhpI_bI
@snarfed.org Wow, that was a blast from the past. My father, a professor of engineering from Sweden, used to speak admiringly of his Jo Blocks.