Veritas Carpenter's Gauge

Yes, using the diameter scale on this Veritas carpenter's gauge, you set it to the width of your workpiece and mark a line from each side; the two lines land very close together, and the point halfway between them is the center.

For marking-gauge use, you rotate the pin carrier to the marking position and set the radius scale to the distance you want, then run the reference face along the edge of your workpiece to score a line at that offset.

Yes, most standard pencils twist into the molded retainer for a snug fit, so you don't need a special replacement lead.

Rotate the pin carrier back to its stored position after use so the point sits protected inside the cavity molded into the pencil retainer.