In the grand tradition of the celebrity chef-conceived 30 minute meal that patently cannot be assembled, prepared and cooked in 30 minutes, I present for your delectation, the second of my 30 minute mod constructions.*
On this occasion, the assembled parts constitute a hotchpotch of the recently acquired combined with bits and pieces I’ve had rattling around for years, waiting for a suitable application. At this seasonal time, perhaps we can liken this to a boxing day bubble and squeak assembled from warmed over turkey, mixed in with a mash of roast potatoes and brussel sprouts, fried to a golden hue in some ruddy cold-pressed rape seed oil.
- One empty bead-blasted Seiko SNK case, purchased on a whim, for no particular purpose other than as a potential rainy day diversion.
- One brand new Seiko 4R36 hand-windable, hacking, automatic movement, complete with a separate dedicated winding stem.
- One sterile Yobokies SM300 style dial.
- One set of beefy, pilot-style hands, sourced, as far as I can recall, from 10watches.com 6 or 7 years ago.
- One red-tipped PloProf-style seconds hand, possibly of MkII origins
1. Fit the movement in its movement holder, noting the familial resemblance to the 7S26/7S36 that has served as the mainstream workhorse automatic movement for many hundreds of different Seiko models since the mid-1990’s.
A considerable refinement of the 7S26 was introduced in 2006 as the 6R15, featuring a Spron 510 mainspring, hacking seconds and hand winding. The 6R15 was fitted to a number of middle market watches of the period and subsequently spawned, in a down-graded form, the 24 jewel 4R36 we meet today, also featuring hand winding and hacking but having to make do with a traditional mainspring. The movement runs at 21600 bph, promises reasonable daily rate variation out of the box and a 40 hour power reserve.
2. Fit the dial to the movement. This requires no more effort than locating the two dial feet in the appropriate holes in the movement main plate and then gently pressing down the edges of the dial until it sits flush with the dial spacer ring. On the 7S series movements, the dial is just held in place by friction, no retaining screws necessary.
3. Fit the hands. With a watch featuring a calendar mechanism, this requires you to adjust the watch forward to the point that the date just tips over. At this point, ensuring the movement is not running (not an issue with seconds hand hacking), carefully press home the hour hand. Depending on your preference, you can then opt to fit the minute hand straightaway but it can sometimes be the case that some slack in the mechanism might then result in a slight misalignment. So I tend to wind it forward through 9 or 12 hours and then fit the minute hand making sure I am happy with the alignment of the hour hand in doing so. At each point, we check that the hands are parallel with the dial and with each other with no prospect of the hands coming to blows on their journey around the dial. Assuming that has all gone to plan, the seconds hand is pressed home and we are greeted by something that is starting to look like a watch.
I’ve tried these hands before on a larger diver’s watch and somehow they did not pass muster and so am hoping that this time around, with the smaller case, they’ll work better.
4. Test fit the movement to the mid-case, checking that the dial spacer ring is of the correct dimensions to allow the correct fitment of the case back. I should confess at this point that I had assumed we’d be ok on that front before going ahead with the dial and hands fitting. We are after all concocting a 30 minute mod and a bit of slap-dashery is therefore permitted.
5. Swap the stem fitted to the crown that came with the case with the 4R36 stem. The 7S26 stem is not profiled to operate the hand-winding feature of the newer movement and so the stems need switching. You can get an idea of the subtle differences between the two in the photo below (the 7S26 stem is on the left). This is a slightly fiddly process requiring liberation of the old stem (heating the crown briefly on a gas burner to melt the glue that helps secure the stem to the crown), cutting and sizing the new stem and fitting that to the crown, secured with a dab of Loctite 222.
6. Grease the crown and case back gaskets, fit the crown and stem and tighten down the case back.
8. Season to taste with a suitable strap, set the time and enjoy.
* An account of the construction of the first can be found here.
This is an older one, but I came across it while looking for other’s experiences, since I’m planning something similar. How did you feel the hand winding worked with the recessed and rather small crown that comes with this case? I don’t have the thickest fingers, but I’m still slightly concerned that getting a good grip in the winding position might be difficult.
On an automatic watch you only ever really need to hand wind to start it up if it’s not been worn in a while. On this, from memory, there was enough room to gain purchase but it’s been quite a while and it is long since gone!