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Location: Perth, Western Australia, Australia

I have spent a life time working with wood now retired and still working with wood finding new methods of using the World's most versatile Woodworking tool The Router

Sunday, May 21, 2006

Mortice and Tenon Joint

Investigate the various methods of constructing a Mortice and Tenon joint with the router
The Mortice and Tenon joint has been around longer than I have, and over the years I would have produced a great number of projects where the joint played a major roll in the construction. Going back to the days when the router had not been part of the average woodworkers tool kit, and the joints were cut by ‘hand’, or you may have been lucky to have access to a Morticer that was available in some professional woodworkers workshop. After a long period of time cutting such a joint and teaching others how to make them, I finally decided to look for an alternative method of producing the Mortice and Tenon.

Looking through books and magazines I began to investigate how others were keeping up with technology and I observed how the router was being used to make the joint using one of the following methods.
· Constructing the Mortice and Tenon joint with the router inserted in the router table such as The 'Triton Router Table.'
· Routing Mortice joints using the accessories supplied. (Side Fence Attachment) Note: The side fence attachment was not considered suitable for cutting the Tenons, and therefore an alternative method had to be found.
· The Tenons were either cut on the circular saw, router table or constructed from a variety of Jigs designed by a large number of Router specialists. (Today there are jigs readily available for purchase to rout the Tenon).

Some of the ultimate jigs published over the years are considered complex in construction, and are never used by the average woodworker for that reason, ‘Too Hard' to make. It could also be said, “What there is to know about routing the joint has been published before and therefore there is no need to write any more”.

Illustrated on the following pages are samples of the various conventional methods followed with an alternative method of producing the joint. With the alternative method detailed below the router is used exclusively with the aid of template guides after the construction of a simple jig in your own workshop.

Router table or Side Fence Attachment?

Routing mortices with the router set up in the router table or with the side fence attachment are the most common methods used by the average woodworker

Review of both methods:
It is important to consider the various all the various methods available of producing the Mortice and Tenon Joint to ensure we are working with safety.

Router Table
This method has been published on many occasions, and each author with his/her own method explaining how the mortice can be cut when a straight cutter is placed in the router inserted in the below bench position.

Note: The cutter is projecting above the table surface and therefore should be treated with

The fence is then adjusted, to position the Mortice, usually in the centre of the material with the operator 'lowering' the material on to the cutter. Two stops should be attached to the side fence, to control the distance of cut. The timber is lowered on to the cutter then moved to the fixed stop. It may also be necessary to clamp an additional fence to keep the material tight against the Fence. (Clamps are not shown in the diagram but are essential to hold the fence secure).

When lowering the material on to the cutter it is important that it is in contact with the backstop, to prevent any kickback.

When the router is used in the 'Table Mode' it is necessary to select a suitable router that can be easily adjusted to the various heights. The depth of cut is adjusted in stages to reach the final depth. Under no circumstances should the depth be set at full depth of cut the mortice.

For the following reasons, the author does NOT take advantage of this method for cutting mortices.
· The cutter is always projecting above the table.
· The cutter is not in view during the operation.
· Both hands are required to hold the material to be cut.

Side Fence Attachment
The side fence attachment for the router may be
supplied as a 'One piece' accessory, or in two sections as illustrated in the diagram. The side fence attachment is added to the router, from the right hand side when facing the front of the router.
In the majority of cases the cutter is set in the centre of the material and the size of cutter selection is usually 1/3rd of the thickness of the material.

The material should be held secure in the vice and consideration should be given to make an additional fence (Jig) that can be attached to the movable jaw of the vice. This additional fence will give greater support to the router base, and increase the length of material for the router fence to follow.

To regulate the required length of the mortice, adjustable stops can be added to the special jig to control the router travel. The stops may require resetting for each mortice.

Disadvantages of this method
1. The router is difficult to control due to insufficient router support
2. Material is difficult to hold, and position each time, especially smaller sectional material.
3. Stop and start distances can be difficult to maintain constant size of mortice.


Consider an alternative method.
This is by no means the 'Ultimate' jig for the construction of the mortice and tenon joint as I am sure someone will come up with a better method.

All the details have been entered on the CD-ROM 2 Illustrated amove Email me for details


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