Projects: 1995 Seiko 7T27-7A20 'Gen 2'

Seiko 'Gen 2s' are another regular in our workshop. This example was acquired ex-MoD with a broken crystal and non-running, but otherwise in very good condition. The case parts were stripped and ultrasonically cleaned, with new pusher gaskets fitted and greased before refitting the pushers. The broken crystal was replaced using a new OEM crystal gasket. The movement was fully stripped, cleaned and rebuilt, with all functions working correctly.

The movement plates and bridges and about half of the gear train is made from plastic and some of these parts are prone to wear and sometimes need to be replaced. The hour wheel is a often damaged, and the two intermediate wheels that drive the 24 hour register can also suffer minor wear and damage. This causes the 24 hour register to gradually move out of synchronisation with the main register over time. Again the only solution is to replace those wheels.

We sometimes have comments from people about the 24 hour register, as it has a bit of play and can move slightly when the crown is pressed back in after changing the time or date, and sometimes it is not 100% synched with the main register. It is worth noting that the 24 hour register is not an accurate time recorder, but is more of an indicator of whether the main register is showing AM or PM. There are 5 wheels in the train that drive the 24 hour register and a little bit of play is present even in a brand new movement, and this only increases as the wheels (especially the plastic ones) start to wear. So, expect a bit of play in the 24 hour register!