| Mortise gauge | |
| Other Name: | Mortice gauge[1] |
| Classification: | Woodworking marking tool |
A mortise gauge or mortice gauge is a woodworking tool used by a carpenter or joiner to scribe mortise and tenon joints on wood prior to cutting. Mortise gauges are commonly made of hardwood with brass fittings.[2]
Like the simpler marking gauge, a mortise gauge has a locking thumb screw slide for adjusting the distance of the scribe from the edge of the wood. It has two protruding pins, often called "spurs",[3] which are designed to scribe parallel lines marking both sides of a mortise at the same time.[4] One of the pins is adjustable, attached to a sliding fence,[5] so that mortises of different widths can be marked.
Some mortise gauges are designed with one retractable spur, so that they can be used as marking gauges as well;[6] however, because the mortise gauge is an expensive and high precision tool, many carpenters prefer to have a separate marking gauge for general use.
For complex joints, some mortise gauges have a double-beam design which allows the gauge to be wrapped around a tool such as a chisel for extra accuracy.[7]