27 Jan 2011, 10:40
All the early Seikos have glass crystals (unless someone has cut a plastic replacement). They used different types of glass on different models and while some are "soft" and comparatively easy to grind & polish any with "Hardlex" crystals are a lot more work. Grinding/polishing glass is an art- check out some of the amateur telescope mirror making sites for a step by step guide to doing this.