Assemble Watches
Start here.
Assemble Watches is a planning tool. It helps you figure out what parts to buy, whether they fit together, and what your build will look like before you spend a penny. This guide explains how to use it, and points you to the best resources for actually doing the mod.
How to plan your first build
The watch builder walks you through the process in four steps. It takes about 20 minutes to put together a solid parts list from scratch.
Start with a movement
The movement is the engine inside the watch, and it's where you start. Your choice here sets which dials and hands are compatible, so it makes sense to lock this in first. The NH35 is the most common starting point for most Seiko builds.
Pick your dial, hands, and case
Once the movement is selected, choose a dial, then hands, then a case. The builder shows options that work with what you've already picked. Each part listing includes dimensions, compatibility notes, and supplier links.
Open the watch builder →Check compatibility as you go
The builder does its best to surface compatibility issues as you select parts. It's primarily a visualiser, so treat any warnings as a prompt to double-check with the supplier before ordering rather than a guarantee of fitment.
Save and share your build
When your list looks right, save it or copy the share link. Post it in r/SeikoMods or send it to someone who's done it before. Getting a second set of eyes on a parts list before ordering is genuinely worth it.
Where to learn how to mod
Assemble Watches handles the planning side. For step-by-step modding guides, these are the resources most people in the community point to first.
Namoki Mods
Beginner's guide and build tutorials
Namoki is one of the most trusted suppliers in the Seiko mod community. Their blog covers beginner guides, step-by-step build walkthroughs, and tool recommendations with photos throughout.
Lucius Atelier
Parts maker with a solid modding blog
Lucius Atelier makes well-regarded aftermarket parts and publishes genuinely useful modding guides on their blog. Good for understanding the process from people who build the parts themselves.
r/SeikoMods
Community wiki and resources
The most active Seiko modding community online. The subreddit wiki has guides, build logs, a parts compatibility FAQ, and a supplier list maintained by the community. If you have a question someone has already answered it here.
Tools you actually need
You don't need a full watchmaking bench. But you do need a few things, and skimping on them is where most beginners come unstuck. A £3 screwdriver kit from a pound shop will scratch your case, strip screw heads, and make you angry. Buy decent tools once. Read the full tools guide →
Links marked → go to a supplier. We may earn a small commission at no extra cost to you.
- Spring Bar Tool →Absolutely essential. You'll use this every single time you change a strap. Get one with a forked end for lug bars.
- Case Back Wrench →For screw-down case backs. A universal wrench covers most Seiko backs; don't improvise with pliers.
- Hand Setting Tool →A basic hand setting tool. Essential for dial and hand work. Don't try this with tweezers.
- Rodico Putty →A waxy cleaning putty for picking up dust and fingerprints off dials and hands. Cheap, indispensable, use it constantly.
- Watchmaker's Loupe (5–10x) →Not essential, but it definitely helps. For checking hand clearance, spotting dust under the crystal, and generally not going in blind.
- Crystal Press →Only needed for crystal swaps, but if you're planning one, don't skip it. Using a poor quality press can damage the crystal.
Helpful reading before you order
Worth reading before you commit to parts.
Ready to put something together?
Browse compatible parts, check dimensions, and preview your build before anything gets ordered.
Common questions
- What is Assemble Watches?
- It's a free watch mod planner and parts catalogue for Seiko platforms. Select a case, dial, hands, bezel, and bracelet, verify compatibility automatically, and generate a parts list with supplier links — all before you buy anything.
- What is the easiest Seiko mod for a beginner?
- A strap or bracelet swap. It requires only a spring bar tool, takes under 10 minutes, and carries no risk of damaging the watch. A bezel insert swap is the next step up, around 15 minutes once you've done it once.
- Are SKX007 and SRPD parts interchangeable?
- Most aftermarket dials, hands, and bezels sold as SKX-compatible also fit the SRPD (5KX series). Always confirm with the vendor that parts are listed as compatible with both platforms before buying.
- How much does a Seiko mod cost?
- A basic mod (strap or bezel swap) costs under £30 including tools. A full dial and hand build with sapphire crystal is typically £80–£150 in parts. A complete build from a donor case usually ranges from £150–£300.
More questions? See the full FAQ or look up unfamiliar terms in the Glossary.