(One in an occasional series.) The photo linked below shows a tool or
jig I designed a few years ago and use maybe every six months or so.

The only clues I will give are that it is made of oak wood, in one
piece (neither of which are critical to its function) and is about
16 inches long.

The first person to guess its design use gets a virtual laurel wreath
to wear for a day. Ready, set, GO!

John Grant

 [ Mystery Tool du jour
 [ https://www.mmdigest.com/Attachments/21/04/30/210430_163408_Mystery_Tool-4.jpg