In recent weeks, I have been tinkering with a new jig for making mitre joints for box making.
Like the Mitre Maker, this jig is for use on the router table using the same flush trim router bit as used by the Mitre Maker. The jig simply and securely holds boards at 45 degrees to the table surface while you run the flush trim bit along the cutting edge.
This mitre jig has a few features that I have transferred over from the Mitre Maker including:
• The compact laminate base for durability;
• An inset t-track arrangement for a spring loaded clamp to hold the workpiece down;
• An aluminum fence and stop arrangement as used on the Mitre Maker for setting the board length and accurate trimming to length;
• Additional fence pieces to prevent tear-out of the workpiece; and
• Machined out 45 degree supports to allow me to use additional clamps if required.
The jig allows me to simply and accurately cut mitres on boards using my table mounted router. Flipping the board over and running the jig against a fence allows me to machine spline slots along the length of the mitre joint or even completely hidden spline slots.
This jig is a tricky one to build accurately, but the results so far have been quite acceptable.
Mounting bearings on router bits of other fixed angles will mean that this jig could be used to cut boards for boxes with more than 4 sides without the need to recalibrate anything.
