with a "little delay"... just 10 years from your post... today i tested my 1.5mm mild steel rorty seat.
here is the picture:
i have to open shoulder's wings a bit, for me is too strict.
at the moment the general feeling is good about the position, not so good about the rigidity. but i still have to weld the doublers all around the perimeter. i will start adding 1 doubler outside, if still be too flexible i will add another inside. i think also the mounting plates need to be reinforced a bit, thinking about weld large inox washers around the holes..
at the end i will also "bomber-ize" the 50mm holes with a dimple die. this should give a little more rigidity.
anybody can post some pictures about upholstery"for idiots"? i found something in youtube but.. very complicated in one side/very different kind of seats in the other.
Originally Posted by alga
I would suggest looking at the Rorty Design seats, they seem to be a bit more refined that the book ones. The drawing is available for free at the Rorty web site: http://www.rorty-design.com/files/Ro...%20Pattern.pdf
Rorty specifies 2.5 mm 5052 or 5251 ally, which should be equivalent to about 1.2 mm mild steel. Could any engineers confirm or correct?
I found on the internets that substituting ally for steel sheet reduced the weight by a factor of 2, which means that the seats have to use 1.6 mm sheet and will weigh about 9 kg each. flyerncle, you were spot on!