Make this handy little gem for less than $5. You'll need one piece of hardwood for the beam and another for the fence. You'll also need two 1/4-20 threaded inserts and a thumbscrew. Drill a hole through the fence for the thumbscrew, 1-1/2-in. from one end. Then rip the fence into two pieces. Cut a dado for the beam in the center of the top piece. Enlarge the drilled hole in the bottom piece and install one threaded insert. Glue the pieces back together and bandsaw a kerf up to the beam opening. Install the other threaded insert in the beam, 3/4-in. from the end. The pencil threads into this insert, so it really stays put. On the beam's other end, I installed a hardened screw after grinding the point sharp, to use for scribing.