Using the TecTool Two-cutter Plough Plane. The Tectool cuts alternately in both directions and the shaving thickness is controlled by the angle the engaged cutter makes with the work. With the body of the tool kept parallel with the surface of the work a fine shaving is produced. A slight rocking motion will produce a thicker shaving. Heavy pressure should never be used. It is not necessary to remove the cutters from the frame for sharpening, but when changing cutters be sure the key is fully inserted in the head of the socket screw. the exact groove width required may be chosen by staggering the cutter (see illustration). Washers, paper, cardboard any kind of packaging can be used for offsetting the cutter to the exact distance required up to a full 3/16. Very wide grooves are cut in stages from left to right. The 1/16" cutters must always be seated on the washers provided otherwise they will dish and snap under pressure of the socket screws.
All these advantages over the old type Plough plane? 1 Works to a stop 2. Cuts any exact chosen groove width. 3. Grooves in a hollow. 4. Grooves around a bend. 5. Grooves on an angle. 6. Cuts dovetail housings. 7. Works against straight edge. 8. Grooves down 1/16" 9. Adaptable for cross grain grooving. 10. Variable shaving thickness control. 11. Long cutting edge life and resharpening without dismantling. 12. Reversible for left handed users. Manufactured by the Tectool MFG., Rainham Rd South Dagenham Essex.
No illustrations, source:
http://www.worthpoint.com/worthopedia/vintage-woodworking-tool-tec-tool-312791258