From 7S26 to NH35: The Best-Value Upgrade
Upgrade Your Old Seiko
If you own an older Seiko with a 7S26 movement, upgrading to an NH35 transforms the watch. Here is why it's the best-value mod there is.
What You Gain
| Feature | 7S26 (old) | NH35 (new) |
|---|---|---|
| Hacking seconds | No | Yes |
| Hand-winding | No | Yes |
| Accuracy potential | +45/-20 sec/day | -20/+40 sec/day (often better regulated) |
| Date quickset | Via hands only | Crown position 1 |
Hacking Changes Everything
Hacking means the second hand stops when you pull the crown — letting you set the time to the exact second. The 7S26 can't do this; the NH35 can. Once you've had hacking, you never go back.
Is It a Direct Swap?
In most Seiko cases, yes — the NH35 shares the 7S26's mounting footprint. Check dial feet positions and stem length, but the swap is one of the easiest upgrades in modding.
Frequently Asked Questions
Does the NH35 fit my vintage Seiko?
Most 7S26-era cases accept it directly. Verify dial compatibility — see our movement guide.
Cost?
An NH35 movement costs less than a professional service of the old movement — and adds features. See the collection for complete upgraded builds.