Want to know how to open a Seiko watch? There are three basic types of case backs your Seiko watch may have: a press fit type case back, a screw down case back, or a screwed down case back.
The tools needed to open a Seiko watch are:
- Watchmakers case knife
- Appropriate sized screwdrivers
- Adjustable case opener
- Soft cloth to lay watch on
- Case holder nice (optional)
- Paper cup
- Inspect case back to determine what type it is. If it has a series of regularly spaced slots along the edge of the case back, it is a screw down case back. If it has four screws along the edges of the case back, it is a screwed down back. If it has a groove or slot along the edge of the case back, the case it is a press fit.
- Select appropriate tool. For the press fit case back, you need the case knife. For the screw down, you need the adjustable case opener, For the screwed down, you need the screw driver.
- Put watch in case holder. If you have a case holder, put the watch in it following the instructions for the holder. If you do not, lay the watch down on a soft cloth.
- Move on to appropriate instructions for each type of case back. In the next sections, there will be instructions appropriate to opening your Seiko watch and its specific type of case back
Press fit case back opening procedure:
- Slip the edge of the watch knife into the slot or gap along the edge of the case back. Make sure that the blade of the knife is away from your hand in case it slips.
- Gently twist the blade sideways. Apply pressure and twist the blade to pop open the case. It's similar to opening an oyster. Once the case starts to open, work your way carefully around the case until the case back pops off. Take care during this procedure not to slip and cut yourself or scratch your watch.
Screw down case back opening procedure:
- Make sure you have room to work before starting. On some watches, the band will not allow access to the case back.
- Remove watchband if needed. Follow the watch's instructions and remove the band if needed.
- Fit adjustable case opener to case back. Fit the appropriate lugs on the case tool into the slots in the case back. It will take some adjusting to get it in place correctly. Patience will insure a proper fit. Tighten it down until it does not slip free. Take care not to slip and scratch the case back or watch. This is where proper fit come in.
- Open watch. Unscrew the case back in a counterclockwise motion until it comes off. Work slowly and be careful; you do not want to wreck the gasket and have to replace it.
Screwed down case back opening procedure:
- Select the appropriate screwdriver. Make sure that you have a screwdriver that fits perfectly. A sloppy fit here can wreck the screw.
- Turn out screws. Unscrew each screw and put it aside in the paper cup. This will help keep from losing tiny screws.
- Pop off case back. You may need the case knife to slip under the edge and pop off the back. Be careful of the gasket.
Tips & Warnings:
- If the gasket gets damaged, it needs to be replaced or the watch will no longer have any water resistance.
- It is recommended to read instructions before opening your Seiko, especially if it is under warrantee. There is the possibility that opening your watch may void some type of warrantee, especially in divers' type watches where water resistance is important.