Singer's instructions imply that these gears should not apply any pressure on each other. So it sounds to me like you did the right thing by backing off a smidge. Lots of older machines use a plastic gear on a vertical shaft that drives the zigzag mechanism. Some of them are on eccentric shafts which allow the gear mesh to be fine-tuned. My general POV is to use the tightest coupling that allows the gears to rotate freely, without any binding.
Last edited by Precaud; 02-01-2026 at 07:56 AM.