The Cross House
Restoring the sash was relatively easy, and this was done ages ago.
What has taken a lot of time was creating a new sill. The original was profoundly rotted.
In 1894, when the sill was first installed, it was part of the entire frame, and all this was certainly pre-assembled on a work table, and then the whole “box” set in place.
Then, 124-years later, taking out the rotted sill was easy, but getting a new sill back in place was not. And the new sill also had to be beveled and mortised and planed, first.
But…all is well now, and the new sill is pressure-treated so that 124-years from now somebody will not be cursing that they have to replace a rotted sill.