Thanks for the ideas. As I do not have a Bridgeport milling machine laying around, making an accurate "chinaman" like that in the link Dan provided, would be difficult for me. I will have to figure out another solution. I wish the B&J had Crown Graphic style fold away stops. For now, painfully careful focusing will be the answer.
Where's your imagination? http://www.amazon.com/Tools-Combinat...824418&sr=1-12
You may want to mark the rails for each lens. To make life easier for yourself, set up your pair of stops for y'r 90, if necessary position them behind the standard. Doing this requires that the 90 make infinity on the outer bed. If it doesn't the "drop the bed, run the standard off the inner rails, raise the bed, pull the standard and bellows out and put the standard on the bed rails from the front" trick won't work.
Oh, and by the way, you don't have to make a chinaman or several yourself. SKGrimes will be happy to make one or several for you. They made the one I use with my Century Graphic.
When there are infinity stops correctly placed for the longest lens used on a B&J press, Chinamen are easy to fabricate. I'd set up a fence on a table saw and make them from sheet aluminum with a fine-tooth blade. Less intimidating material than aluminum should also work. Some models of B&J require a cutout in a Chinaman for the front slide lock, others do not. If a B&J has no infinity stops, a properly made Chinaman that precisely fits either inside or outside of the rails can insure the lens and the film are parallel. The longer that Chinaman is, the more accurate it can be. Making such a Chinaman is easy enough for a competent machinist with precision tools, or possible for a master craftsman with primitive tools. If one doesn't want to wrestle with machining a precise one-piece Chinaman, A sheet of metal or other stable material can be fitted with sliding or rotating cams that can be adjusted to a camera that is perfectly aligned. Then the cams can be pinned in place to prevent further change. As Dan suggests, use your imagination. Reduce a problem to its most basic elements and build a solution from that. Too often we complicate problems with a surplus of sophistication.
Not as accurate as the metal spacer, but perhaps easier, just requiring drilling a scale rule.
The scale can be non destructively mounted on the bed using existing screws. ( At least, on the 4x5 Speed)
Then record the infinity settings for the lens in the book.
That way, I can use , say, the old Computar variable focal length 105~150mm lens hand held with the roll film back.
Here is a photo from that lens with the RH-8 back. ( when set to 135mm, the native rangefinder on the Speed is accurate)
https://app.box.com/s/aqvznhvq37b4pwuyfupv
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