How much does a Seiko mod cost to build?
Parts, tools and the extra costs to budget for when building a 36 mm Explorer-style watch around an NH38 movement.
My 36 mm Explorer-style build uses an NH38 movement, a case set, a dial and three hands. There’s no donor watch to buy. Once you’ve chosen a strap or bracelet, that’s the watch paid for. If you’re starting from scratch, you’ll need to budget for tools as well.
Prices have been fluctuating a lot. Something you buy today might have been $30–40 cheaper only a couple of months ago, so an old video’s parts total can be well below what you see at checkout. The prices here follow my gear list which I try to keep updated but check the seller’s price before ordering.
What goes into the watch
The case set includes the crystal, caseback, crown and stem. Check the contents of the listing you order from, particularly whether a bracelet is included.
| Part | Listed price | Notes |
|---|---|---|
| Seiko NH38A movement | $125 | No-date movement for a dial without a date window |
| 36 mm Explorer-style case set | $40 | Includes crystal, caseback, crown and stem |
| Explorer-style dial, 28.5 mm | $8 | Confirm diameter, feet and layout before ordering |
| Mercedes Style Hand Set | $4 | Check the hand fittings match the movement |
Add delivery, tax and a strap or bracelet to these prices. The part names link to the listings I use. They’re affiliate links, so I earn a small commission if you buy through them, at no extra cost to you.
I used the NH38 because this dial has no date window. An NH35 would leave a date wheel turning behind the dial and a quickset position on the crown with nothing visible to adjust. If you want a date or a GMT hand, the NH movement guide covers those choices.
Tools: the first build costs more
Start with the tools listed in the build tutorial and cross off what you already own. A beginner kit covers several jobs. Check its contents before buying separate hand pushers, a cushion or a blower, or you’ll end up paying for the same tools twice.
You’ll also need a way to hold the movement, measure and trim the stem, and close the caseback. Good lighting and magnification help when fitting the second hand. The tools page lists the equipment I use.
Calipers, tweezers and hand pushers can serve you for years. Gasket grease and thread locker get used in tiny amounts. You have to buy them for the first watch, but most of that purchase will still be on the bench for the next one.
The costs that are easy to miss
Shipping adds up when the movement, case and dial come from different sellers. Compare the delivered totals, including tax, before choosing between listings. A cheaper part can cost more by the time it reaches you.
It’s a good idea to order a set of spare stems. Once you’ve cut one too short, it needs replacing, and waiting for another delivery can hold up the whole build. A spare set of hands is useful too, especially for your first attempt at fitting the second hand.
If you plan to wear the watch in water, ask a local watchmaker what a pressure test costs and add that to the budget. The rating on a case listing doesn’t tell you whether your finished assembly seals properly.
Is building one cheaper than buying one?
Sometimes. Having the tools already makes a big difference. For a first build, compare the whole order with the price of a finished watch, including delivery. A low parts total isn’t much help if you still need to equip the bench.
For this Explorer-style watch, the appeal is choosing the dial, hands and case and putting them together yourself. If that sounds like a good evening, the build tutorial takes you through it.