This is the Groove Tube-Grove Cutting Tool from Great Planes.
This tool cuts perfect grooves in balsa for installing
elevator joiner wires, aileron torque rods and bearings,
tailgear wires and bearings, or to clean pushrod exits in fuselages.
FEATURES: Creates crisp, clean grooves in balsa by using a back and forth
Creates a uniformly round groove that increases the rod's
performance - without the need for sanding.
Much safer than using a hobby knife or drill to gouge out the wood.
INCLUDES: One Groove Tube Cutting Tool (in a storage tube, mounted on a
photo illustrated header card with useage instructions.
SPECS: Groove Cutting Tube Length: 4" (112mm)
Diameter: 1/8" (3mm)
Plunger Rod Length: 5-1/8" (131mm)
Plunger Spring Length: 1-1/2" (40mm)
COMMENTS: Caution: Always grasp the part behind the sharp edge of the cutting
tube, and cut away from your body.
For hard balsa, make two or three shallow cuts rather than one deep