Simple, non-complicated micro focuser by f0x_. I just found the focus ring was breaking too easily after a few attempts. May be able to rotate the original in your slicer to get horizontal lines for strength but at the cost of too much support material. I just beefed it up a little. I also printed at 100% infill as it is a small part and only a few extra minutes in print time. Probably not necessary as 60-80% would suffice.