You've seen the builds on Reddit. A stranger's SKX case with a sandwich dial and a snowflake hand set that shouldn't work together but somehow does. Now you want one that's yours.
The NH35 is the obvious place to start. It's the automatic movement powering half the Seiko mod scene, it's cheap to source, and it's forgiving enough that a first-timer with a case wrench and a steady hand can get through a build without ruining anything expensive. This is the part list and the assembly order, plus an honest read on when to build it yourself and when to pay someone else to do it.
The Parts You'll Need
A watch build breaks down into eight or nine components, and getting the compatibility right matters more than getting the individual pieces right.
Movement. The NH35 is a hacking, hand-winding automatic with a date complication. Its cousin, the NH36, adds a day wheel in two languages instead of one. For a first build, NH35 keeps things simple.
Case. SKX007 style cases are the standard starting point, and many aftermarket dials, hands, and bezels are cut to fit them. Case diameter, lug width, and crown position all need to match your movement and your strap choice before you buy anything else.
Dial. This is where the build gets personal. Sandwich dials, sterile dials, chapter ring dials — pick based on the hand set you're planning to run, since some dials need specific hand lengths to clear the markers properly.
Hands. Sword, snowflake, Mercedes — whatever you're going for, hand length has to match your dial's chapter ring diameter or you'll get hands that either fall short of the markers or hit the crystal.
Bezel and bezel insert. The insert is the colored ring capping off the bezel — dive timer, GMT, or a plain color. This is one of the easiest ways to change a watch's whole personality without touching the movement.
Crystal. Flat sapphire, domed mineral, or the original Hardlex — each changes how the dial reads under light and how legible your lume is at an angle.
Crown and gaskets. Get the gaskets right and your watch is water-resistant. Get them wrong and it isn't, no matter how good the rest of the build looks.
Strap or bracelet. Lug width and spring bar length need to match your case. This is the last decision and, honestly, the one most people change their minds about six months later.
If you'd rather not source eight components separately and hope they're all compatible, the Project MM1 Pioneer Edition bundles a matched case, dial, hands, bezel, and NH35 movement for S$199 — usually cheaper than buying the same parts as a donor watch plus mods.
Step-by-step assembly
1. Prep your workspace. A case cushion, a set of case wrenches, tweezers, and a dust-free surface. Dust under the crystal is the single most common first-build regret.
2. Install the movement into the case. Seat the movement holder ring first if your case uses one, then drop the movement in and check it sits flush before moving on.
3. Attach the dial. Line up the dial feet with the movement's mounting holes and press gently until it seats. Don't force it — if it's not lining up, the dial feet position probably doesn't match your movement.
4. Set the hands. Hour hand first, then minute, then second. Use a hand-setting tool rather than tweezers alone; it's the difference between hands that sit level and hands that wobble every time the watch ticks.
5. Fit the crystal and gaskets. Seat the gasket in the case groove before pressing the crystal down evenly around its edge. Uneven pressure here is how crystals crack or gaskets crimp.
6. Mount the bezel and insert. Check the bezel action before you consider it done. Most bezel inserts either click in place or require adhesive to be secured.
7. Install the crown. Screw or press it in depending on your case type, and confirm it seals tight against the case tube.
8. Attach your strap or bracelet. Spring bars go in last, once you've confirmed everything else fits and functions.
9. Set the time and test the hack. Pull the crown to the second position — the second hand should stop. That's your hacking function confirmed working.
How hard is this, really?
For most of the steps above, not very. Movement, dial, and hands are straightforward if you've got basic tools and you go slowly. Where people run into trouble is gasket seating and crystal pressing — both are easy to get wrong in a way that isn't obvious until the watch fogs up after its first shower.
If you're building for the experience and don't mind a redo, do it yourself. If you're building a piece you want to wear daily and trust with actual water resistance, a local watchmaker can press the crystal and check your gaskets for the cost of an hour's labor. Plenty of first-time modders do the fun parts — dial, hands, bezel selection — themselves and outsource just the crystal and case-back seal.
Why Build One At All
Every SKX-based Seiko off the shelf looks like every other SKX-based Seiko. The moment you swap the dial, pick your own bezel color, and choose hands nobody else paired with that combination, you've got something that doesn't exist anywhere else. That's the actual point of modding — not just cheaper access to a nice watch, but a piece where every choice was yours.
*Image used were generated with tools for purposes of accompanying the article only. It does not reflect actual products.