Medium density fiberboard (MDF)

A special type of tempered hardboard characterized by a very fine, smooth finish. MDF is used in cabinet making.


To alter a board with a cutter, blade or bit.

Mill Marks

Small parallel ripples or ridges produced on the surfaces or edges of wood by planer knives, joiner knives or saw blades. In the case of planer or joiner knives, these imperfections can be caused by nicks in the blades, improper knife settings, feeding the stock too rapidly or taking too deep of a cut in a single pass. In the case of saw blades, virtually all blades (with the possible exception of certain hollow-ground blades) produce mill marks.


A joint where the meeting angle of two pieces of stock is divided. For example, the 90 corner of a picture frame is usually created by cutting two mating 450 miters. This same 900 corner angle could also be divided and produced with a 60 cut and a 30 cut.

Miter gauge

A tool that slides in a slot on a power tool such as a table saw, router table, bandsaw, etc. A miter gauge can be adjusted to different angles and is used to slide the stock past the blade.

Miter-and-spline joint

A joint with two mitered surfaces connected by a spline. (see spline)

Moisture Content

A measure of the amount of water in a piece of lumber.


The process of creating decorative surfaces on workpieces using a molder accessory.


A hollowed-out hole or recess that is usually rectangular in shape and formed to accept a matching tenon for joinery purposes. Mortises can be created with a mortising bit and chisel, a router bit, a series of overlapping drilled holes or an ordinary hand chisel. Mortising is the process of cutting such a hole or recess.

Mortise and Tenon joint

A joinery technique where the tenon from one board fits into the mortise of another.