Step 3: Make the device part 3
Lay it on the riser so the pencil is on the center line of the base board.
Adjust the holder so it is at a right angle to the riser.
You must fix one piece of wood to the top of the riser so it will be tight against the holder.
At the other side of the holder you need to fix a wooden wedge ( blue in the drawing ) fairly close to the holder but not touching it.
The other piece of timber ( red ) which is again a wedge is used to keep the pencil holder in place.
That's the device finished.