A long shot this. I don't have a digital camera or scanner so I'm hoping someone might identify from the stamped inscription and the following.
Base part twelve inches by four, machined underneath with two quarter inch square alignment strips which would seem to locate into slots. Has three bolt slots with machined faces on one half (which presumably are to bolt the thing onto a machine), and a vertically slotted hole in which sits a one-inch diam. "bolt" with a pin which engages in the slot. The top of the "bolt" is rounded fore and aft presenting an edge contact across the width. A knurled collar with four holes around the circumference screws onto the "bolt" to allow vertical adjustment, the pin-in-slot maintaining alignment. A stud either side fitted to the base carry a clamping bar which is also rounded for and aft. The other half of the base is machined with an undercut slideway. Stamped DME 692/2.
The other part (three and a half by two and a half inches) is machined to slide on the base, engaging with the slideway, with gib strip and finger lock-nut which tightens the gib. Upper surface is machined as two V-blocks across the width with four threaded studs, clamping bars, and nuts and washers. Will hold bar from about one and a half inches down to aboutthree-eighths. Stamped DME 693/2.
The sliding part says "use me to drill or mill bar", but the "bolt" and collar and the clamping strip seems to be designed to hold something at an acurately set height. All I can think of is drilling or milling slots in a T-piece made of round bar where the down part of the T has to be raised or lowered according to the diameter of the bar to ensure the hole is at right angles to the T surface. Pretty unlikely, especially since the v-blocks part can be moved four-plus inches with respact to the "bolt" and collar, which suggests a much more univeral tool.
No points for guessing this is the first time I've tried describing a tool without pen and paper. Hope someone can understand and identify. TIA.
Ken.