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Steve Salmons
1-Jan-2017, 07:03
I recently bought this rather unusual large format (5x4) technical camera for which information is very, very thin on the ground. It dates from the early 1950s and was made in the UK by G H Williamson of Oxford and Marketed by Dawe Instruments Limited. It is also sometimes known as the Nelrod Universal to distinguish it from the Nelrod Liteflash Press camera made by the same company.
In most ways it is similar to the much better known MPP Micropress or Graflex Speed Graphic and I am very used to the way the focal plane shutter works on these cameras but the focal plane shutter on the Dawe remains a mystery despite much playing around with it..
When I first received the camera the focal plane shutter was not working at all as one of the tapes had become twisted out of position. Putting this right and a squirt of solvent spray into the winding mechanism has rendered the shutter mechanism working but I simply cannot work out how to set the stated speeds. It has a peculiar arrangement whereby the speeds are only visible when the GG back is removed. An indicator specifically states 'Set Here' (see pic) but there does not seem to be anything else available to allow the setting
If anyone is familiar with this bit of voodoo I would very welcome a pointer in the right direction.
Also there also appears to be a model 1714A and I am wondering what the difference between the two models might have been.

Steve

Plungefrog
1-Jan-2017, 08:58
Possibly a daft question, but is there anything on the curtain that can be aligned with the dots at the edge of the frame?

Steve Salmons
1-Jan-2017, 09:30
Possibly a daft question, but is there anything on the curtain that can be aligned with the dots at the edge of the frame?

Nothing I can see. Seems to be a fixed width opening on the shutter with the speeds being governed by a change in tension when winding. There is a knob simply marked Max in black and Min in red which I guess corresponds somehow to the speeds marked on the scale. This does have an effect upon the speed at which the shutter fires but I can see no way of matching it to a specific shutter speed.

Steven Tribe
1-Jan-2017, 10:20
Frustration is the name of the game with most aged focal plane shutters! I guess that this shutter has been modified and was originally a two curtain type.

This looks like an adjustable window size version, where the size of the window is adjusted after placing the top of the window corresponds at the top mark. The bottom of the window is adjusted to the to the line corresponding to the required speed. Obviously, there must be a device for which from the low tension to a high tension (the inner scale) - the max/min you mention!

Dan Fromm
1-Jan-2017, 10:53
Hmm. This is reminiscent of the Pacemaker Graphic curtain shutter, which has three openings and two tension settings, giving six shutter speeds.

Steve, how many openings does the beast's shutter have? If six, there has to be something that indicates how far the shutter has been wound up. 1, 2, 3, 4, 5, 6. Also, firing the shutter should let just one opening pass through the gate.

The max (black) and min (red) control selects the spring tension. If it is like the Pacemaker Graphic, it will allow only two choices.

Ron (Netherlands)
1-Jan-2017, 11:56
In picture 1 that shows the back and side of the camera, there seem to be two winding knobs at the side - I guess one for tensioning the spring like you mentioned and the other for winding the shutter. I have 3 German cameras with somewhat comparable shutters. In these cameras the winding knob also makes it possible to adjust the curtains' opening which is done by pulling out the knob and turn it in one or other direction. Perhaps this should also work on your camera: pulling out or pressing the winding knob and turn it in order to adjust the gate.

There might have been little dots stamped on the side of the curtain which correspond with the dots on the side in your photo..

IanG
1-Jan-2017, 13:19
I have adverts for these cameras and quite possibly some other info in BJP Almanacs, they weren't made for very long, I think they only advertised twice in the Almanacs.

My assumption is the shutter is quite different to a Graflex/MPP Micro Press possibly having two shutter curtains and the markings on the back in the first photo are for setting the slit width, I've seen this on old focal plane shutters. It may be that's where you position the edges of the curtains before finally tensioning.

Ian

Steve Salmons
2-Jan-2017, 05:58
Thanks for the responses everyone. The adjustment of the slit width is the at the root of the problem.159331159332159330

The Max /Min knob has not 2 but 8 click stopped settings. There are 6 sets of fast/slow speeds marked on the back so if one assumes that the spare 2 click stops correspond to B and T the alignment of either the top or bottom shutter edge with the speed markings would make a lot of sense. However this is where the problem comes. No matter what I do the slit width does not seem to vary. It remains at the full width of the film back.
By holding in the small black shutter release button (shown)below the rangefinder window I can align the top edge of the bottom shutter or the bottom edge of the top shutter with the marked speeds but when the shutter is fully would the slit width remains at it maximum.
I do find that when the tension is set to its higher settings (Max 1 or 2) the shutter fires faultlessly. At lesser tensions it has a tendency not to fully complete its travel.
It could be that there is a fault with the max/Min setting knob that would explain why the slit width does not change but without confirmation that this is the case by comparison with a working model I would be rather loath to dismantle. The front shutter is working well so for user purposes the problem is purely one of interest.

Steve Salmons
12-Jan-2017, 11:13
Well I finally had to put my hand in my pocket and buy a copy of the user manual and I'm glad I did as this camera has a couple of quirks that I would not have found out about without it. Firstly the focal plane shutter whose setting was causing me grief. The manual confirms the correct usage as follows: The first shutter is wound so that its bottom edge is level with the 'Change Here' mark. The shutter winding knob is then pushed in firmly and held in while the bottom shutter (top edge) is wound to align with the desired speed marked along the edge of the film back (see earlier pic). The winding knob is then released and the rest of the wind on continued in the normal position. This effectively changes the slit width. The tension button is then set to maximum or minimum depending on whether you want the slow or fast speed indicated. This was the functionality that was failing on my camera. However a further hour of tinkering finally revealed another small problem that was causing one of the shutter tapes to get stuck during its travel . Once I had managed to unpick this, everything started working. Hurrah! Feeling very smug :D.
However things just got better as the manual revealed the nature of the intermediate tension settings. These allow for the fine tuning of the speeds. As it happens the absolute minimum tension setting was not allowing the shutter to fully complete its travel when fired. But move the tension settings a couple of notches in the direction of maximum and problem solved. I suppose a similar action is possible if the fast speeds are firing too fast. Just move the max tension setting down a notch.
In addition to this the rangefinder set up is geared to wide angle, standard and telephoto lenses so different cams are not required for different lenses. It is simply a matter of sliding a cursor on the rangefinder arm to a position where the rangefinder infinity coincides with the infinity setting on the distance scale. It can then be locked with its thumbscrew. You would then double check against an object placed at a known distance (say 6 feet) from the camera to ensure that distance scale and rf are in agreement with the image on the GG. It's a bit fiddly to get to the thumbscrew but infinitely easier than adjusting a Kalart rangefinder: for that life is just too short. The camera also has easily accessible screws for vertical and lateral rangefinder image adjustment.
I may well find a few more surprises yet as I have not yet fully explored the movements