A combination machine is a device used in woodworking which combines several woodcutting functions into a single machine, rather than requiring individual machines for each function. Using a combination machine presents the woodworker with distinct advantages and disadvantages, and the usefulness of the machine will depend largely on the type of woodworking being done and the location in which the machine will be placed. Many woodworkers who purchase such a machine do so to cut costs and to cut down on the amount of space taken up within a workshop.
The specific functions of a combination machine can vary. Sometimes tools that are fairly similar will be combined into one machine for convenience. A thicknesser and a jointer, for example, are often combined into one machine because they perform fairly similar functions but are different enough that a user would otherwise need two separate machines to perform the tasks. A thicknesser creates a board of uniform thickness by planing it, while a jointer creates a flat surface on one side of the board. In some cases, a board must go through a jointer in order to be put through a thicknesser with effective results. Such a combination machine is sometimes known as an over-under.
The advantages of a combination machine are varied. One of the draws for many woodworkers is the savings both on space and cost. A combination machine will prevent the woodworker from having to buy several machines for the same tasks, thereby lowering the initial investment cost of setting up a workshop. By featuring several tools in one location, the woodworker will also cut down on the amount of space used in the workshop. This is especially important for home woodworkers or those professionals working with limited space.
A distinct disadvantage to the combination machine is the time necessary to switch between functions. A woodworker who creates several pieces during a set time period will find himself having to switch between functions on the machine several times, which can add to the time it takes to finish a piece. This disrupts workflow and can lead to degraded efficiency, meaning the woodworker may lose money in the long run. Some professionals argue that combining several important functions into one machine ensures each function will be substandard, as opposed to machines that are designed solely for one purpose. Modern combination machines have greatly improved, though time will still be lost to adjusting the machine for different purposes.