When the device is to be used as a gauge for straight-edged
boards, as in fig. 3, the block C had better be clamped
by means of the screw c, and can then be used on either side,
as on the upper side of the rod A, marking-pins, h h,
are secured, as shown.
When used on curved edges, as in figs.
1 and 2, the block C should be left free to slide, while
B is fixed. The four ends of the two fingers E will
always be in contact with the edge of the board, and
will thereby insure that the rod is held at right angles
to the edge, and as they turn on their pivots, with
their inner ends forward, on concave edges, they will
cause the block C to slide backwards, and with their
outer ends forward on convex curves, they will cause
the block C to move forward, and as they are previously
properly adjusted, they will in this manner always keep
the point a the required distance from the edge.
To set the block C at the required distance
from the point a, the screw b is turned so as to release
the block B, when the two blocks, B and C, are by one
movement adjusted nearer to or farther from the said
point a, and clamped by means of the screw b.
I claim as new, and desire to secure by
Letters Patent—
The fingers E E, pivoted on the sliding
block C, and operating so that their four ends will
always remain in contact with a curved or straight edge,
substantially as herein shown and described.
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