Instruments for Alining the Knife and Nosebar on the Veneer Lathe and Slicer

Veneer must be uniformly thick and smooth to assure high quality plywood. To obtain uniform thickness and smoothness, the knife and nosebar on the veneer lathe or slicer must be properly positioned. Two instruments were developed at the Forest Products Laboratory for setting the knife angle and the horizontal opening between the knife edge and the nosebar. The knife angle indicator is made by combining a machinist’s protractor with an accurate leveling bubble. The short arm of the protractor is provided with a flat plate that fits against the ground surface of the knife. Two small brass pins protrude near the top of the plate. These pins may be fitted over the edge of the knife in order that the instrument will not be tilted while in use. To the longer arm of the protractor, a machinist’s precision level is attached. A 4-inch level with a ground and graduated vial has been found satisfactory for this use. By adjustment of the horizontal arm until it is level, the angle at which the knife stands may be read directly to a fraction of a degree on the vernier scale of the protractor. Conversely, if the knife is to be set to a certain angle, the angle is preset on the protractor, and the instrument is clamped in this position. The instrument is then placed against the knife, and the carriage is tilted until the proper setting has been made. An accurately calibrated dial-gage indicator, reading to 0.0001 inch, is used in the construction of the horizontal-opening indicator. The dial-gage indicator is mounted on a flat aluminum block, with its stem inserted through a hole in the block in such a way that it can be moved to obtain a zero adjustment. One surface of the flat plate, which is intended for contacting the ground surface of the knife, is provided with three brass shoes that extend slightly beyond its surface, When the instrument is in use, these three shoes are placed firmly in contact with the ground surface of the knife. The stem of the dial indicator projects above the knife edge until it contacts the edge of the nosebar. The dial indicator then shows, to an accuracy of 0.0001 inch, the magnitude of the horizontal opening between the knife edge and the nosebar edge.

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