Wes K wrote: ↑Sat Jun 25, 2022 1:44 pm
I have a "procedure" I like to use for adjusting the half-nuts I'll share with you, read thru it and proceed with caution, as you can easily damage these delicate parts. The feedscrew and half nut should be in good shape with no pitting or scratches before you start.
1. start with your machine having the reproducer carriage and the tube that slides on the carriage rod assembled no the machine without the feed nut spring and guard. the carriage assembly should slide back and forth very easily when lowered into playback position. If it does not slide back and forth easily, fix this first.
2. You need to be careful doing this step. Loosen the clamp screw that secures the carriage to the tube. Loosen this crew several turns. Use a small, thin screwdriver and put it in the slot in the carriage above the tube and push it in until the tube turns easily inside the carriage. Use extreme care doing this, push the screw driver into the slot only enough that the tube will rotate without much effort. The screw driver you use should also stay in the slot on its own once you have it where the tube turns.
3. Have your half nut and spring assembled together. Put a drop of oil on the center of the feedscrew and then place the half nut on the feed screw over the oil drop and make sure the nut is seated on the screw. Have the end of the spring that attaches to the carriage tube pointing up about 45 degrees. Use the thumb and first finger of the left hand to hold the half nut/spring assembly to the feedscrew together for the next few steps.
4. slide the carriage over and rotate the feedscrew down so that the screw holes in the spring and tube line up. Rotate the tube as you line up the holes so that the flat surface where the spring mounts is flat with the spring. Put the feed screw guard on if you have one, but have the adjusting screw in the guard backed out so it is won't touch the spring.
5. Tighten up the two screws that hold the spring and guard to the tube. Once they are tight, you can release your death grip holding the half nut to the feed screw.
6. With the carriage down in playing position, and the feed nut still on the feed screw, remove the screw driver from the slot so the carriage will clamp down onto the tube again. Tighten the camp screw.
7. Raise the carriage so the half nut raises off the feedscrew. Turn the adjusting screw down until it just touches the spring, and no more.
8. Without a record, operate the machine in playing position in 2-minute mode and watch and listen for skipping from the half-nut. You may need to adjust the screw in the guard a little. Just a tiny fraction of a turn makes a big change in feed screw tension.
9. If the carriage moves from left to right without skipping, try playing a record and listen for dragging or slowing down. The half nut needs to push down of the feedscrew only enough to propel the carriage and no more. It will drag the machine down if it is too much.
I hope this helps you out!