Answer: they had fans
Parallel keys are the most widely used. They have a square or rectangular cross-section. Square keys are used for smaller shafts and rectangular faced keys are used for shaft diameters over 6.5 in (170 mm) or when the wall thickness of the mating hub is an issue. Set screws often accompany parallel keys to lock the mating parts into place.
Metal tabs in the structural wall are mortared between the stones to tie everything together to prevent the stonework from separating from the wall . Slipform stonemasonry Slipform stonemasonry is a method for making stone walls with the aid of formwork to contain the rocks and mortar while keeping the walls straight. Short forms up to two feet tall are placed on both sides of the wall to serve as a guide for …
Insulating concrete form – Wikipedia
Key (engineering) – Wikipedia
Framing – Wikipedia
Firewall (construction) – Wikipedia
Sat Jun 18 2005 14:30:00 GMT-0400 (Eastern Daylight Time) · Framing in construction is the fitting together of pieces to give a structure support and shape…