I just aquired what appears to be a pacemaker 4x5 speed graphic with a side mounted Kalart shutter and a body shutter release. There's one control on the focal plane shutter that I'm not clear about: the shutter winding key makes sense (this selects what shutter speed you get), as does the front/back shutter selector (this controls if the body shutter relase sets off the focal plane shutter or the front lens shutter). However, there's a small silver lever at the bottom of the focal plane shutter control panel, just about at the bottom of the camera, which one picture I've found of the camera labels "speed control lever." Could someone tell me what purpose this control serves? Thanks.

It controls which of the two speed ranges are used with the focal plane shutter. I don't have mine in front of me now, but if you look at the little window that displays the speed (after the shutter is wound), then move the little lever, you'll see the speed in the window change. At one setting the top speed is 500, the other setting is 1000, and so on down the list...

Ah, that makes sense. I didn't see the shutter speed window changing when I played with it before, and now I do. Thanks!