Have you recently changed the grind stone/sleeve and nut?
The mainshaft bearing has been replaced on the shaft in the wrong place, so that the side arm is sticking in the feed column guide channel.
Look for “rubbing” between side arm and channel and re-position main bearing so that the side arm is free and in the centre of the guide channel.
To check, bounce on the handwheel, side arm and shaft should move up and down freely with no sticking, or Lift the side arm and shaft and let go, it should fall freely back onto the feed nut.
The stone may need dressing – dress the stone.
There may be some vibration resonance – try varying the reel spin speed.
The collar (Stone carrying Sleeve and Nut) may be worn.