Continuing adventures in 3d printing, I had a double pane window fail and got a $1,100 quote to replace it. In the end the failure was the “shoe” locking mechanism inside the counter-weight system. Although there is no counter-weight like a windows from the 1700’s that Nash might have installed, but four coil springs. The rest of the window was fine. I designed and printed replacement parts which you can find here on thingiverse.
Nash, by the way, designed all those beautiful houses around Regent’s Park. Notice the sash windows. These have counter-weights in them, or at least did a few hundred years ago:
The original shoe in my (crappier, more modern) windows used a fairly small amount of plastic at the most stressed part of the design. Failure of decade-old plastic mechanical parts appears to be a common thing, and it looked as if designed to fail exactly when the warranty expired.
I wonder if the designers were designing this to fail on purpose or really thought the thing would last. It’s possible they thought the plastic wouldn’t become so brittle, yet it’s clear they were minimizing the amount of material used to make it. This reminds me of a carrier furnace I used to own where they made the drip pan out of a rusting metal. Some bad design is so egregiously bad it strays in to being plain immoral, like the Bronco roof which couldn’t support its own weight and would kill you if it rolled.
The wonderful thing about 3d printing is, nobody has to design these things ever again and you can go print them out of titanium if you want to.