Simple woodworking mortise and tenon

I am a total newbee. I am trying to design a basic mortise and tenon and my problem is I don’t know how to create the cavity in a solid box that would represent the mortise. Could some one help me with the basic hand-holding operations?

Sure, no worries! I use Rhino for macOS, but the process on Windows is the same.

  1. Create the box to subtract from with the required dimensions with the _Box command.
  2. Create the box that the tenon is attached to, with your required dimensions with the _Box command. You can for instance create it at the origin and then move so that it aligns with the first box. Another, quicker method could be to _Copy and scale the first box.
  3. _Hide the first box.
  4. With the DupEdge command, duplicate the four edges of the face, where you want to create the tenon on the second box. The four edge curves still selected, Join them into a closed polyline curve.
  5. Now use Offset to create the outline of the base of the tenon.
  6. Extrude the new base polyline curve with ExtrudeCrv to a desired distance or tenon size. Make sure that the Solid is checked.
  7. Unhide or show the first box with the _Show command.
  8. Make a copy of the tenon geometry. Simply select it and use CTRL + C and CTRL + V. This will create a copy on the same layer and in the same location.
  9. With the _BooleanDifference command, first select the initial box and press ENTER, then select the copy (or original) of the tenon geometry, and again confirm with ENTER.
  10. If desired, you can also join the remaining tenon geometry and second box with the _BooleanUnion command.

thanks very much!! The GIF is super fast, but combined with the enumerated text I will get this done. The number of command options is daunting, but there-in lies the power too! Again, many thanks.

draw 3 boxes that make up the parts of the joint.

boolean subtract for the pocket, boolean union for the post. Don’t delete boolean parts between steps.