Graflex lensboard Lock Hardware- Original and modified
I have a 4x5 Speed and now I am preparing a 2 x 3 Crown.
Both are in good shape except the lensboard locks were a bit loose.
I made neater (?) sketches of what I did here in case it is of use to anyone with similar loose locks.
Firstly I sketched out the original design from the 4 x5 parts list (The 2 x 3 Crown uses identical parts except the lock plates are smaller.)
The problems with aging of the original design, is that washers go missing, the wear loosens the locks, the nuts start to pull through the soft bellows flange, and the screws tend to bind in the original nuts , they are then difficult to tighten because there is no way to hold the nuts from turning.
I took all the hardware off both cameras and re-assembled correctly on the 2 x 3 ( Option '0" of my sketch). However the locks were still rather loose.
So the inner washers were removed and the outer washers were replaced by metric M3 washers which are thicker and of larger outside diameter while still being a good fit on the original Graflex special screw ( Option 1 of my sketch)
That fixed the 2 x 3 Crown.
I use heavy medium format lenses on the 4 x 5 Speed, probably heavier than the design intended.
On the lathe I machined new Tee nuts with larger outer diameter to better clamp the bellows flange and thicker so they can be gripped with pliers for tightening.
Instead of making a stepped bolt, I used 4 more identical T nuts and M2 stainless machine screws. The larger diameter on the front helps hold the lock plates parallel to the lens board. (See Option 2 of my sketch and the dimensioned sketch of the new T nuts.) There are 8 required per camera.
That fixed the Speed, now the cameras can be held by the straps without fear the lenses might fall off.
Meandering marsupial, you may have omitted something important. The conical "nuts" that attach to the screws that hold the lensboard sliders also hold the front bellows frame to the front standard. If all this is assembled correctly, nothing should pull through the front standard.
I've had a loose slider problem with one of my 2x3 Crowns that turned out to be due to one little washer too many. There should be two washers, one between the slider and the front standard, one in front of the slider.
Yes, that is correct, my new nuts are of a larger diameter to clamp the bellows flange -even if the slots are worn oversize.
The original screws are possibly 5-40, a standard but not common size. A google search found them at http://www.instockfasteners.com/index.asp . A 4-40 nut and screw can be substituted for the existing 5-40. A 3mm metric screw needs a .0995 pilot hole. A 5-40 needs a .0995 pilot hole. A #39 drill bit is .0995. The existing nut may be stripped to mid way and using a 1/8 inch longer screw adds 5 threads that will grip in the rear of the existing nut. The end of the screw should be flush with the nut to prevent damaging the bellows. A 4-40 requires a .0890 pilot hole. A #43 drill bit is .0890.
The original screws were special Graflex parts I think.
Screw part number 30401-P1 has a shoulder under the head, 0.110 dia by 0.075 inch long.
That shoulder has to be a close fit in the angled slot of the lock.
The long nut , had part number 30377-P1.
The replacement M2 screws I used fit nicely in the holes in the standard
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