I have been enjoying my Crown so much that I have acquired a Speed stablemate. Probably not the only person to have done so. I have some nice barrel Dagors to use with it. Basically sound; members have helped me with a few missing peripheral bits, the only mission-critical item is the Ektalite, hopefully I'll find one, otherwise I'll shim the ground glass.

There is a missing screw under the trip/back/front switch, the screwhole is exposed when the switch is in the 'front' position. What function does this scew perform? (I don't see it in the service manual.) Do I need to worry about its absence?

It was a nice surprise to find it was a military issue, presumably from around 1950 from the serial number. Does the AF-8340 order number mean it was for the Air Force?

Well the AF means that it was purchased by the Air Force. But since the military expands and contract faster than an accordion in Frankie Yankovic's hands, at least at one point, the Air Force was purchasing a lot of stuff for all three branches of the military.

http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf

See page 11 for assembly diagram

Oops. pushed buttons too fast. Do you think it is posible that this was an aftermarket mod to "lock out" that switch?

I don't think so; I can't see any abrasion, wear or scarring on the top edge of the slider. There appears to be the tip of a screw screwed in from the inside in the corresponding position at the bottom end of the slider's travel. The odd thing is, neither of these seem to appear in the assembly diagram.

OK, thanks for the followup pic... that was a question I had. In a 1966 Navy Photographers Mate training manual there is a couple of pics of this part of Pacemaker Graphic. It looks like the top hole had a screw from behind -- just like your most recent picture of under the bottom part of the switch slide. The repair manual isn't very clear on this -- unless that screw is the bottom screw depicted as holding in the gear assy (parts 6 & 7) onto the shutter plate. If so, I would suspect that your camera wouldn't be winding or releasing very smooth, if at all.

Brian hadit right the first time. For some reason, someone drilled and tapped that hole. As a lock out? Looks like that would be the case.
Set the rear shutter to Open, insert a screw and you can't accidentally close the rear shutter, limited to front shutter, and thus pretty much a real heavy Crown Graphic.
Should not effect opperation of camera; you just have an extra hole so your camera is a tiny bit lighter.

The C-6 was made in a couple of different flavours for the Air Force, one by Graflex (the Pacemaker Speed that John has) and another completely different 4x5, made by Beseler, that is very rare and a good find these days.
I have a Pacemaker C-6 at home so after work I'll have a look and see if it has the extra screw in the shutter selector.
Cheers, Bruce

Just arrived home, dragged the C-6 Pacemaker off the shelf and mine has no screw hole or raised screw head, just a sunken screw head the same as the bottom one on John's shutter selector switch, and the same as the bottom one on mine.
John's is maybe a custom mod, but who could guess when it was done.
Cheers,
Bruce

Thanks everyone for all the info. It's a relief not to have to worry that the shutter could disassemble at any moment! And interesting to learn a little about the model history.

I do have a question about the shutter release. On my camera it seems to take place in two steps. Initial pressure and travel of the release causes a very faint clunk. At this point the shutter has not fired. Finger can be removed from the release button, which will now move without resistance over the ground already covered. A firmer (but not excessive) pressure on the release fires the shutter. This two-stage release occurs with both the body release and the slider. Is this normal?

Sort of like taking up the slack on the trigger of one of my Enfields. But on the rifle it is more defined, whereas on the two Speeds I just checked out, it isn't enough of a stop to prevent firing the shutter.
I do have a sideplate assembly apart right now and can check out the thing later and see if I think the partial release was intended.
I think it is just the way the catch plate pulls out and lets the gear move slightly. It is however a defined sound and motion that when you mentioned it I knew exactly what you were referring to.

It is designed to have a half catch release as described.

The wind key is attached directly to the master gear. on the back of the master gear there are two pins that are the stops that catch inside the spring loaded escapement assembly. This assembly is pushed up directly by the slide selector switch and releases the master gear, which is turned by a small gear at the end of the upper roller.
Anyway, the catch at the of the escapement mechanism has a step purposely built into it. Two-thirds main catch, one third secondary step and then releases. Very touchy though.

I checked my smaller 23 series Speeds and they have this also. But not the Miniature Speeds which have a later release mechanism like the Aniversary etc...