827A Starrett Single End Edge Finder .375 body diam X .200 contact diam.

827A
Starrett Edge Finder (single end)
.375" Body Diameter

For fast, accurate work location
Work surfaces may be located easily, quickly and accurately with these
edge finders. Work with flat, straight edges, shoulders, grooves, round
work, studs, dowels or center points and scribed lines ? all can be
accurately located with this handy tool. Body and contacts are made
of tool steel, hardened, ground and lapped to close tolerances for
diameter and concentricity.
How To Use:
Edge finders are easy to use. They are placed in a collet or chuck. The
worktable is then traversed to obtain contact between the rotating
edge finder and the work. Contact will shift to concentric position
relative to the body and with very slight additional table adjustment,
will move off center with a decided wobble. At this point, the center
of the finder is exactly one-half the diameter of the contact from the
work edge, permitting accurate location for other machining operations
relative to the edge.
For locating center points and scribed lines, the pointed contact is used
by putting a pencil or rule against the center point and making it run
concentrically. Then the point is brought down to the center point or
intersection of scribed lines and the table is adjusted so that when the
tool barely touches the work, the lineup with the point in question can
be ascertained.