Logs longer than 18 inches will not fit my fireplace so I made a log marker to ensure that they are the right size. This marker works best after falling and de-limbing the tree. One end has a sharp point the other has a grease stick type marker.
To make this you will need a length ( A little longer than your required firewood length) of 1/8 X 1/2 metal bar stock.
Step 1: Drill and Tap a Hole at One End for the Pointed Screw
I put a point on the 10-24 screw and locked it in position with a nut.
Step 2: Drill Clearance Holes for the Handles.
You can put them anywhere you would like the handles to be. I drilled and tapped the end of my handles for 8-32 screws.
Step 3: Drill and Tap 8-32 Hole in a 13 Mm Socket
Drill out the square end of the socket with a drill just a little larger than 13 mm.(maybe 5/8 inch if your socket OD allows for this)
Drill a hole in the side of the socket for a 8-32 screw to lock the marker pen in place.
Grind or mill or file a semi circle In the end of the bar stock and weld a 13 mm socket to it.
My socket got slightly skewed due to the heat of the weld hence the small bend in the bar stock near the socket to compensate.
My description of method is not great but most people could make this just by looking at the photo. Just make sure the distance between the pointed screw and the marker tip is the length that you need for your firewood.