Building a surprise gift watch for Roberto

This year we had another addition to the family when my stepdaughter Lauren married Roberto.  As a "welcome to the family" gift for him, I decided to build a custom watch.  According to Lauren, he tends to wear larger, bolder watches.  In this photo I see an Invicta Russian Diver automatic, a Rolex Submariner clone, and a Sanwood quartz (Aliexpress brand).

So I wanted to choose a design that would be big on the wrist but with a classic heritage.  The selection of replica watch style parts is limited to a few styles, (Rolex, Omega, IWC, and Panerai come to mind). I wanted to base it on a Unitas 6497/6498 movement, and that limited it to IWC and Panerai with larger cases.

I had seen a article about how large watches, particularly Panerai, had been popularized by Sylvester Stallone in the 1990s, and I thought it would be fun to see what model(s) he wore and whether I could replicate it. Turns out he wore a Panerai Luminor during filming of the 1996 movie "Daylight" (link), and it boosted the trend toward big (44 mm and larger) watch cases.

Panerai started building the "Sly Tech" series of watches which now sell for $25k-40k on the used market (see this one).  This 5218-205A model served as the target for my design. This model not exactly like the one in Daylight, but I prefer it because it has a seconds hand in the sub-dial at 9:00. (By the way, the actual watch Stallone wore in the movie sold for $214,200 at auction in 2020.)

I found a nice copy of the Panerai Luminor watch case with a sapphire (very hard to scratch or break) crystal, a display back, and water resistant seals.  Panerai was asked in 1935 to make watches for the Italian Navy, which is why these models have dive watch features. Here's an article with the history of Panerai Luminor if you are interested.

The most distinctive feature of the Luminor case is the locking crown guard, which is designed to compress the crown (the thing you turn) against the case with a rubber O-ring in between to seal out any water.  It also ensures that the crown cannot be broken off by impact or accidentally pulled out to the setting position, which could result in the time changing.

The case back has a large display window to show off the design of the movement and to see the gold balance wheel moving back and forth exactly 3 times per second.  You can also watch the wheels (gears) move when the watch is wound. 

Anyway, the next step is to source the parts and tools.  Here's what I used:

Parts:

1. Watch case - Panerai copy with sapphire crystal and display back, designed for the Unitas 6497/6498 movement and clones like the Seagull ST36.  The case has O-rings for the case back and crown to give good water resistance.
2. Movement: Unitas 6497/6498 manual winding mechanical clone (ST36)
3. Dial & Hands - Panerai replicas with black dial and orange/yellow numerals. I decided to deviate from the original design by including a small seconds sub-dial at 9:00 so it is obvious that it's running.  The hands are white with black border matching the original design (with the addition of the small seconds hand).
4. Strap - The original came with a sharkskin leather strap with buckle. I found a store online in the Netherlands that sells one nearly identical to the original.
5. Bonus strap - I added an orange silicone strap for an optional sporty look.
6. Movement clamps - The movement I found did not appear to come with clamps and screws to secure the movement to the case, so I ordered 5 sets (need only 2 sets).
7. Winding stems - It's easy to snap a stem with the Panerai style folding crown lock if it's not cut to exactly the right length.  Turns out I did not need extras.
8. Gift box - A gift box is great for storage and to make it a proper gift.

New tools in addition to my standard watchmaking tools:

1. Case back wrench - This is a special opener for 12-sided Panerai style case backs.  When I fixed a friend's Panerai clone watch I used a mini bench vise to grab the flats of the case back, but I found an opener cheap on eBay.  Unfortunately, this one was not able to fit a the 40mm flats on the case back, so I'm ordering a special tool...
2. Panerai 40mm case opener - This tool makes it easy to screw/unscrew the case back.  I should have just bought this one in the first place.

Here's a photo of my watchmaker bench.

Nearly all of the parts were ordered from Asia and Europe and arrived within 15 days. The movement was first to arrive which was perfect because I wanted to test and adjust the timing.  The Swiss Unitas 6497 manual winding movement was originally built in the 1950s for Panerai.  It is copied now by several manufacturers, and the version I chose is one like used by Panerai with extra decoration -- special machining to catch the light, plus blued screw heads, and a swan-neck regulator.  

None of that makes it tell time better, but it looks cool through the display back. This version of the 6497 is very much like what Panerai used in the classic dive watches.  The first thing I did was put it on the Timegrapher, the instrument used to measure mechanical watch movements.

Out of the box it ran very strong and just a little fast at + 8.5 seconds per day.  That is about as good as it gets with this movement.  I wound it fully and let it run down until it was erratic, and it lasted about 52 hours.  The idea is that you wind a manual watch every morning when you put it on, and set the time if needed.

The black dial has orange numerals that glow green in the dark.  Seconds are counted on the small sub-dial at the 9 o'clock position. The simplicity of the dial layout was designed for high visibility in the dark and/or underwater.  The dial is then fitted to the movement and the three hands pressed onto the posts using a hand press.

After fitting the hands I moved the hands through 12 hours to ensure they do not physically interfere with each other during rotation.  Then the movement-dial-hands assembly is fitted into the case and secured by case clamps and screws (red circles).

I temporarily screwed in the case back and placed it on the Timegrapher to see if it was still in adjustment.  It was still running great at +2 seconds per day, so time to finish casing it.

Next, the winding stem (the shaft that the crown screws onto) has to be trimmed to the correct length.  I probably spent 2 hours just measuring, calculating, cutting, and filing the stem to get the right length.

Then I installed the crown guard for the last time, lubricated the O-rings with silicone, and screwed on the case back.  Before finally closing the case I cleaned both crystals with lens cleaner to remove any dust, smudges or hairs that might be stuck to either crystal.  Then I fitted the silicone strap and took it for a test drive.  (The orange band is a bonus to give it a second more rugged and sporty look.  Amazon has an infinite variety of straps.  Just look for a 24mm lug width strap. It tapers to 22mm at the buckle.

After I build a watch I always wear it for a few days to make sure nothing goes wrong, like a hand falls off inside and floats around the dial.  Or it just stops, or keeps bad time.  I like to set it in the morning then check it against my radio-calibrated clock for accuracy.

Still right on time at 8:35pm!

While waiting for the last items to arrive, I rented the Daylight movie on Prime to see the watch in action and snapped a of pic from the screen:

It was an OK movie, pretty good special effects and lots of explosions, car wrecks, cave-ins, and Stallone saving the day.

And here is a final shot of the completed watch with the sharkskin strap.  I like it so much I'm going to make one for me with a different dial and strap.