Hi Steve,

I like the laser cutting idea very much; cutting the strips by hand definitely counts as 'tedious'.

The taper in the fold widths is a 'convenience' primarily, rather than adding in any extra flexibility. Using expanding and reducing tapers may help reduce the number of folds too, but the advantages are minimal. For example, on my 8x10, the bellows are removable and the bellows support frame for the rear standard is 12" square with a 10" aperture. This gives a 1" (25mm) frame width which is sturdy enough for the size of the frame so it will not break in my camera bag if I have bag bellows in the camera instead. It makes sense to have a 1" fold width a the rear standard as the bellows are easy to mount to the frames and the inner/outer dimensions match the frame size. The front standard plate on the camera has a width of 4 3/4" (120mm) and therefore a 1" bellows fold size does not leave much space for mounting large lenses. Having a bellows fold with of 15mm at the front standard means I can use a lighter construction bellows frame and have more space for large lenses. Therefore having the folds change in size from the rear to the front means that the bellows frames can be made in a proportion that is mechanically suited to the size of each standard.

When I made the 8x10, I wanted it to be compact (well, as compact as an 8x10 can ever be!) so also wanted the bellows to fold as flat as possible. By starting with a 25mm fold width, expanding out to 30mm for most of the bellows, and then tapering back to 15mm, I minimised the number of folds and therefore layers of material. In practice, a taper from the 25mm down to 15mm would have been fine as the bellows fold very flat and a few extra folds would have been tolerable (picture of the bellows is below).

I am in the process of constructing a stereo camera too and there, having a 5mm fold width at the rear standard means the two bellows can fit closely side-by-side. It is far more practical to have most of the folds 10 or 15mm deep running to the front standard however as they will fold flatter and be easier to make. In this case, the fold size would taper in the reverse direction from the rear to the front standard, while the bellows themselves are wider on the rear standard than the front.

I got the idea from an old Kodak folder which had trashed bellows and I noticed that the fold size reduced as they reach the rear standard so that a narrow mounting width could be used. I examined the cardboard lattice from the bellows and then worked out how to apply the tramline taper to recreate the fold tapering effect.

Best regards,

Evan