At times my engineering background not give me rest, and I sometimes do repair and restoration machines. Metal vices were cleaned of rust (for this I used acetic acid). Cleaning in an acid bath, It took a time, probably about 7 days. Next, necessary to gather metal vices and install a new thrust bearing. Gland packing and plastic grease, do their thing: rotation of the trapezoidal screw very smooth. I'm pleased with the result.