Assemble Watches
How to Check Seiko Mod Part Compatibility
To check Seiko mod part compatibility, verify: (1) dial feet match your movement, (2) hand tube sizes match the movement pinion posts, (3) crystal diameter matches the case exactly, (4) bezel ring fits your case, and (5) lug width matches your bracelet. Assemble Watches automates all of these checks as you select parts.
- What compatibility checks matter most for a Seiko mod?
- In order of importance: (1) dial feet pattern matches the movement — NH35/NH36 pattern, (2) hand tube inner diameters match the movement pinion posts, (3) crystal outer diameter matches the case specification exactly, (4) bezel ring fits the case diameter, (5) bracelet/strap lug width matches the case.
- How do I check if a dial is compatible with the NH35?
- Look for dials explicitly listed as 'NH35 compatible', 'NH35/NH36 compatible', or 'SKX007 compatible'. These will have the correct dial feet pattern. Confirm the dial diameter (typically 28.5mm for SKX-based builds) and the date window position matches your movement.
- How do I check crystal compatibility for a Seiko mod case?
- Crystal compatibility is about the outer diameter and the thickness of the crystal's lip. Check the case manufacturer's specification sheet for the exact crystal outer diameter — this is often listed in tenths of a millimetre (e.g. 30.4mm). A mismatch of even 0.1mm can cause fitting problems.
- Are SKX007 and SRPD parts compatible with each other?
- For most aftermarket parts, yes. Dials, hands, and bezel inserts sold as SKX007-compatible usually fit SRPD (5KX) cases too. However, some third-party cases have slightly different bezel diameters or crystal fits. Always confirm with the vendor that parts are explicitly listed for both platforms.
- Can I check Seiko mod compatibility without buying parts first?
- Yes. The Assemble Watches builder at assemble.watch/build checks compatibility as you select parts — dial feet, hand tube sizes, crystal diameter, and movement fit — before you order anything. It's free and requires no account.