Simon
Will get photos of a Grenier hinge on a bow posted later today.
The bow is cut in half at the center of the grip. The the 6 counter sunk holes are used to screw the hinge to the bow. When Nels used Barney's hinge on Bear bows, he covered the hinge with the leather grip.
The advantage of the Barney's hing was both halves of the bow were attached at all times.
Don't believe these guys really had guides for their 1930s and 1940s deer hunts in Michigan. At least not guides in the sense that we think of them today. They were pretty much figuring things out for themselves and setting up their own camp. Don't know how the shutter was snapped for this photograph. Lots to learn and so little time to learn it...
Simon - Just took this photo of the only Grenier Hing I have on a bow that is not covered with a leather grip. You can see it had a leather grip at one time and the hinge is rusted probably from moisture retained by the leather when the bow got wet. Six screws on each half and both halves attached to each other. Nice sleek hinge.