But I guess we should never underestimate how much time and trouble people were willing to take - that's what leads people to talk of extraterrestrials. Some efforts are just mind-boggling e.g. forming the SH lintols, including the tenons, by bashing with a lump of rock.

It's a half inch drill. ;)
What I like about it is that it's cleverly chamfered at the back end such that it can be set into a split stick with a diameter no more than the drill so it can go in to any depth.