A few days ago a question was asked on how I cut compound angle mortises with my horizontal router mortiser. Why might you want to do that? Well, if you make chairs the rail between the front and back legs is often at a compound angle where it meets the legs. Typically the rail angles out and up where it meets the back leg, for example. Here's how I would handle that.

The end of the rail is cut to whatever compound angle is needed. Let's say the rail angles out at 5° and up 2° where it meets the back leg. OK, first I cut off the end of the rail at those angles.





The table on my HRM is set to 5° and the workrest angled to 2°.





And now the mortise is cut.



With both the table tilted and workrest angled the mortise ends up exactly perpendicular to the face of the compound angle cut. But if you'd rather the mortise be parallel with the length of the rail, you don't tilt the table, you just angle the workrest. Now the mortise looks like this.



If you'd rather have an integral tenon you cut those in the same way, only you start with longer parts, obviously, and you cut away material to leave the tenon rather than into the rail to create a mortise. But the principles are the same.

There are other ways to do this but I don't know of any that are easier or faster within the budget of a hobbiest woodworker.

John