A wood planing machine comprising:
- a base having four corners;
- four hollow posts extending uprightly from said corners of said base, respectively, each of said posts being formed with an axial slot for access to an interior thereof;
- four screw rods extending rotatably and uprightly from said corners of said base through said posts, respectively, each of said screw rods having an externally threaded portion that is formed with an external thread;
- a cutter carriage having four corners mounted respectively , vertically and slidably on said posts, and a horizontal bottom surface;
- a transmission unit connected to said screw rods to permit synchronous rotation of said screw rods;
- and
- an error reducing unit including four tubular threaded members that are secured respectively to said four corners of said carriage, that are disposed respectively within said posts in such a manner that said threaded members are exposed from said axial slots in said posts, and that define axially extending threaded bores respectively engaging said screw rods such that rotation of said screw rods results in movement of said carriage along said posts, each of said threaded members having
- an internally threaded portion defining a respective one of said axially extending threaded bores and engaging said externally threaded portion of the respective one of said screw rods, and
- a circumferential slot formed through a wall of said internally threaded portion so as to divide said internally threaded portion into an upper part and a lower part, said upper part being disposed above said circumferential slot and having a bottom surface that defines a top end of said circumferential slot, said lower part being disposed below said circumferential slot and being formed with a vertically extending threaded bore therethrough, each of said upper and lower parts being formed with an internal thread that engages said external thread of the respective one of said screw rods, said error reducing unit further including four locking bolts that engage respectively said vertically extending threaded bores in said threaded members and that press against said bottom surfaces of said upper parts of said internally threaded portions of said threaded members such that said internal threads of said upper parts of said threaded members press upwardly against said external threads of said screw rods and such that said internal threads of said lower parts of said threaded members press downwardly against said external threads of said screw rods so as to lock said internally threaded portions of said threaded members 60 on said externally threaded portions of said screw rods 50.