How to modify your Seiko.

In this guide I will outline how to modify a Seiko SNK809 watch. This watch will receive a new strap, dial, hands, and crystal.

Clean off your bench and get your tools out!

Clean off your bench and get your tools out!


Get that strap off.

Using a spring bar tool, engage one of the flanges on the spring bar and compress it. I use my index finger to push it towards me and for more control. Being careful here will help avoid scratching the case.


Removing the caseback

Using a case holder, secure the watch. I place the case holder into a small desk vice which is stable. Make sure you size your caseback remover and are using the correct dies.

When you go to unscrew the caseback apply downward pressure with your left hand (this prevents slipping) and unscrew with your right. There are other caseback tools that allow you to circumvent this, but are generally more expensive.


Your caseback is off!

And the movement is exposed. A few things you can do at this point, firstly though, be very careful around the balance wheel/hairspring assembly. This is one of the more delicate parts of the watch and touching this is a good way to break or seriously damage your beloved timepiece.

Some people, at this step, like to remove or tape down the rotor so the movement is easier to work with once it's out of the case. Some people also like to use a movement holder.


Removing the crown and stem.

At this step, your crown must be completely depressed. There are 3 positions for the crown on this movement, and they are 0-1-2. Position 0 is completely pressed in. Position 1 is pulled out one click, this adjusts the date and day. Position 2 is pulled out 2 click and adjusts the time.

There is a small lever with a divot in it, this only appears in position 0. Gently press this down and with the other hand pull the crown straight out.



I use a little watch cushion and carefully invert the watch and gently tap the crystal until the movement falls out.





If tapping doesn't work..

Some are a little more snug than others, don't worry! You gently use some tweezers or the smooth end of a springbar tool to lift upwards in the stem hole. BE CAREFUL! Don't go too deep or push too hard, just enough to get it loose then flip it back over and tap it out.


You've got your movement!

With the movement out, put the crown back in. Push it in gently and straight. DO NOT depress the crown release tab when reinserting the stem on the 7S26 (other movements may necessitate this though).

With your crown back in, set your time to 12:00 NOON. Some people like to let the power reserve run out, but it isn't necessary.


Use protection.

Next, the hands need to be removed. You'll need dial protection of some kind. Bergeon makes dial protectors that are pretty thick and in my opinion, a little bulky. I like to use plastic sheet that I cut into a little square. It's kind of like a plastic bag but a little thicker. You can certainly use plastic bag if you want.


Hand removal.

With your dial protection in place get your hand removers, some people like the levers (pictured here) or the spring loaded hand grabbers. Make sure you get under the hour hand and apply symmetrical force, all three hands should pop off.


Dial removal.

There are some notches along the side in the movement ring, these are a good spot to slide some tweezers and wiggle the dial out. The dial has two feet on it which are pressure fit into holes in the movement ring.

dial insert.jpg

New dial.

It's a good idea to use finger cots when handling all the parts housed within the case. Carefully hold the dial by the side and line up the dial feet with their corresponding holes on the movement ring. If your dial has the wrong dial feet or no dial feet you can use double sided adhesive on the movement ring to keep the dial on.

The typical Seiko 5 dial size is 28.5mm. And you can purchase California dials like this one here.

hour hand.jpg

Applying the hands.

With your new dial in place and flat, it's time to apply the hands. The first hand is the hour hand, you want to align this to 12. Carefully hold the hand with some tweezers (some people use Rodico for holding hands) and rest it on the pinion. Use your hand press (with the correctly sized die) to press it on



After you've pressed your hand on be sure to check the alignment. Make sure it's nice and parallel to the dial. Then do the minute hand. Make sure the minute hand is also aligned to 12 (be sure your hour hand hasn't moved!).


Keep checking alignment.

It's very important to make sure your hands are applied properly and have good clearance. Be sure to advance the hour and minutes (before applying the seconds!) to check your application.



Hour alignment.

Your hands, if applied at the correct time (both at 12) should advance properly and land accurately at each hour. If you didn't apply your hands at 12:00, you'll notice that they don't line up at each hour.






Seconds hand

Rest the seconds hand on the center post. If it isn't resting on the center post it is easy to press it between the center post and the cannon pinion-which may result in broken parts. Sometimes it may rest at an angle on the minutes hand and the center post, this is fine as long as it mounts the center post when you press it. Be sure to use the correct die for your hand press. Determining the correct amount of pressure at this step will take some practice. Be patient. The seconds hand does not need to be aligned to any specific hour or minute. Remember to check your alignment.

With your hands applied properly, remove the crown and stem.


Crystal removal.

To remove the crystal from the case make sure you have a dish shaped die that is wider than the crystal, this ensures you wont shatter the crystal when punching it out. You can also use microfiber cloth here.


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Fitting a new crystal.

After you've removed your stock crystal, screw the caseback of the watch back on. Get your new crystal and be sure to handle it carefully by the sides (you don't want to have to clean smudges off the dial side). Try to fit it level into the case with your hands.



Will it press?

If you're using a domed crystal, you'll want the appropriate die. Using one with the wrong edges or profile can break your crystal or apply non-uniform pressure. You may need to apply a bit of pressure here. This step can also take a bit of practice.


Crystal alignment.

With your new crystal pressed in make sure you check the alignment from all angles. 


Casing your movement.

Make sure you've gotten all the dust off your dial. Using the blower on the hands is also a good way to make sure they're secure. Blow out any dust that may be in your case as well.



With your movement on the pad, carefully place the case over top. It should slide in relatively easily if your alignment is correct, be mindful of the stem tube alignment in the case and not to scratch your dial with it.


Finishing touches.

Make sure the movement is pressed all the way into your case, if it is not, the stem and crown will not be aligned. Insert your stem and screw on the caseback. Then go get your new strap and put it on...