Reprinted with permission from MLS Machinery, Inc.
Mortisers and some single end tenoners can be used in door and window manufacturing. This mortiser puts a non-round hole into the edge or top of a piece of wood; it can be square or oblong. Example, this type of hole is basically used for part of the locking mechanisms of a door, or for construction holes in the bottom rails of some chairs or for construction of a frame style door. It will put a non-round hole (mortise - female) into a part when a non-round part (tenon - male) is needed. They are often stronger in certain construction applications than a plain round hole. Example, early American style solid wood chairs, that have a piece of wood going between the legs — (1) to give support to the chair and (2) to use as a footrest.
Some mortisers will do a square or oblong hole without rounded corners and others will do rounded corners. Note the difference between a mortise (female) and a tenon (male). The mortise will always be on the flat surface of the part; the tenon will always be on the end of the part. Manufacturers who need to do multiple holes, example garage doors, use a multiple slot or oscillating mortiser which might have six or seven of these slot mortisers on one machine producing six or seven holes at a time. The square type hole is made with an oscillating mortiser which can be a single or multiple head configuration as discussed above. The cutter or cutters go back and forwards (oscillate) all the time in the wood to a pre-determined size. The part will be put on a table and held down by clamps. The table moves slowly forward into the oscillating cutter/cutters to a predetermined depth; once reached, the table will retract. Some of these machines today are now C.N.C. (computer numerically controlled) which will automatically calculate where the hole or holes should be, how wide, long and deep they should be.
In the case of oblong holes with rounded corners, they work on the same basis except that the cutter itself would be circular instead of oblong therefore leaving rounded corners.
Chain mortisers are also still used. Basically these machines use a chain that is the tool which has numerous cutters on it. The machine almost looks like a conventional drill press with a handle that is pulled down, which in turn plunges the chain into the part that is clamped to the table. The width of the chain will determine the width and length of the mortised hole.
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