Building the "Reprogle Ultra" Chronograph for Dawson's Graduation

Me, Dawson, and Alysa Grady at a Purdue football game in 2023

My son Dawson will be graduating from Purdue Polytechnic University this year, and per tradition I'm building him a wristwatch as a graduation present.

Originally the idea was to try to replicate an Omega Speedmaster Professional "Moonwatch".  Dawson has had a fascination and interest in the history of space exploration, and the Moonwatch was worn on the Apollo missions including the first moon landing.

For whatever reason, however, the watch parts market has not seen fit to provide the case, dial, and hands parts needed for hobbyists to put together a decent replica.  Cheap Moonwatch copies of the made in China exist, but that's not the point now, is it?

Choosing a design triggers a series of interdependent decisions constrained by availability, desired features, and technical compatibility.  Some of those questions:

1. What overall style?
2. What movement/case combinations are available?
3. Which of those fit
4. What movements are available for

Of the other options to include the Rolex Daytona, TAG Monaco, and Tudor Monte Carlo, Dawson settled on the Pilot chronograph style that originated during WWII.  Functionality and readability were the focus of the design, and the style continues to be popular 70+ years later.

Fortunately, one of my favorite watch part suppliers on eBay, SWISS-MADE-TIME, sells all of the parts needed to build and customize a watch based on the proven Valjoux 7750 chronograph movement.

Swiss Made Time also sells multiple variations of the 7750 with assorted features and complications such as: day, date (in various dial locations), moon phase, and quick set.  Besides the complications it comes in three grades: Standard, Elabore, and Top, with added decoration and timekeeping accuracy features.

Valjoux 7750 Top movement with blued screws and day/date

but in the end Dawson chose the original configuration with 6 hands plus the day and date windows at 3 o'clock.  The closest watch on the market to the final look is the IWC Pilot Chronograph 41 Blue Dial (reference IW3881).

For the hands, we looked at several options, and Dawson liked the look of chronographs like Tudor Monte Carlo and Breitling Chronomat with one or more orange hands.  So we decided on an orange sweep seconds hand and an orange running seconds subdial hand.  He made a mock-up in MS Paint with the two orange hands, and that became the design. The only other change was to make the day and date indicators black on white like the IWC above.

One other option Dawson chose was to add a bit of "pop" to the rear view by swapping out the winding rotor.

The final part of the watch design to decide was the strap or bracelet.  The classic pilot watch look includes a leather strap, often with rivets and contrasting stitching.

I had previously purchased custom leather goods from Etsy shops, and in particular I had a watch strap made from kangaroo leather which is very supple.   I ended up custom ordering the strap from TkachenkoLeather in Ukraine.  

Evgeniy makes goods from a variety of exotic leathers, and he was able to meet all of the requirements, except he did not have a buckle to match the matte titanium finish of the case.  After not finding an actual titanium buckle, I found a shop in the UK selling a sandblasted stainless steel buckle that should be a good match per the photo. I had suggested a deployant style clasp to Dawson, but he preferred the basic pin buckle instead.

Besides the watch itself, I ordered a gift/storage box, plus I picked up a nice watch winder I saw on an auction site.  Next comes the waiting for everything to arrive...

Update: 03-Jul-2024

Welp, assembly should have been straightforward, and obviously this update is about 6 months coming.  I received all of the parts (case, movement, hands, gold rotor, custom strap) plus a small jar of orange enamel paint.  I was able to do a passable job of painting the sweep and seconds hands orange, then moved on to building the watch, starting with the dial, then hands.

I was able to mount the dial with no problem.  Being the first chronograph watch I had assembled, I had to install all six hands aligned properly.  And of course the subdial hands are closest to the dial, so it made sense to install them first, then the hour hand, minute hand, and sweep chronograph seconds hand. 

Despite trying over and over, spending hours using different tools and optics, I could not get any of the 3 subdial hands to mount properly.  I began to suspect that the mounting holes on the hands were too small, out of spec, to fit onto the pivots.  I ended up breaking the mounting pin on the time seconds subdial at 9 by using too much pressure with the hand tool.  I ordered a replacement wheel, and in the meantime wrote a message to the ebay seller (S-M-T) and asked for a new set of hands, which they sent for the cost of shipping.  I also ordered a special movement holder for the 7750 to secure it while allowing me to work the chronograph start/stop & reset buttons.

When the replacement wheel arrived, I then had to disassemble part of the movement to install the new part.  Of course, this was not part of the original plan, but I was able to replace the wheel with only a little problem.  Back to square 1.

Then, I tried again to install the hour counting hand at 6.  It was just as difficult and seemingly impossible as the seconds subdial hand.  And I ended up breaking that wheel pin as well.  At this point, I was totally discouraged.  I ordered and received a replacement wheel, but didn't have the stomach to tear apart the other side of the movement to swap the part.  I just put the project down for about 4 months.

I swallowed my pride and decided to seek professional help.  I called a watchmaker in Cincinnati, but he does not like to take on DIY hobbyist disasters like mine. I then contacted S-M-T to see if they would assemble the watch since they will do is as an option when you buy parts.  Julien there said they could do it for $40 and would also be able to replace the broken wheel. The big expense involved is shipping all of the parts to Switzerland, but in the end I bit the bullet and sent all of the parts (minus the strap) to him on June 13, 2024

Part 2

Swiss Made Time completed the repair and assembly and shipped the completed watch on July 17. I received it on July 23, and it looked exactly like I hoped.  I thought they were going to charge me for the assembly and return shipping, but as of 2 days later they had not.  That fact makes me suspect they found something wrong with the hands and concluded my assembly troubles were at least partly their fault.  But it's possible they will ask for some payment later, I suppose.

I set the time, day, and date then put on the custom leather strap to get the full look. SMT also sent a blue leather-ish strap (2nd photo) at no charge.  Dial and hands look very nice.  (Just don't inspect the hands I painted orange under a microscope.)

I did some preliminary Timegrapher runs, and it measured very good with an average +5 seconds per day overall rate with a range of 0 to +11, and strong amplitude in the 280 range.  Overall the performance is close to COSC chronometer spec, which is -4 to +6 seconds.  Movements tend to slow down a bit in the first few weeks, so I don't think it's necessary to change the regulation.  I'll wear it for a couple of days as usual and take some real-world readings of accuracy while being auto-wound and stationary during sleep.

By the way, according to the Timegrapher results, the best position to lay the watch when you take it off is on its edge with the crown up (3U) because the rate is closest to 0 s/d.

Two-day wrist tuning results

Final results of the on-wrist testing show an overall rate of +2 seconds per day over 48 hours.  This included night-time resting in crown-up position.

I purchased a 2-watch travel wallet as the gift box.

Watch in dual slot travel case.

I think he likes it!

Auction find: Patek Philippe Top Hat, reference 1450

When I began this pursuit of repairing, restoring, and building watches, I never thought it might one day involve any kind of high-end watch such as a Patek Philippe.  But with the help of Karen, my treasure-hunting wife, a vintage Patek Philippe 1450 "Top Hat" manual wind watch became ours.

The watch was posted on the estate auction service Everything But the House (EBTH) and listed as "not running".  The posting photos showed that the case, crystal, hands, and dial seemed to be in very fine condition.  The movement appeared clean, without corrosion or damage, and the only really degraded part was the strap, which was black alligator with a (probably plated) yellow gold finish clasp.  The rectangular case is 18k rose/pink gold with hooded lugs and matching dial and hands.  The movement is a caliber 9-90, tonneau/barrel shaped, and manual wind.  The crystal did not appear to match the cylindrical shape fitted to the original Top Hat per photos and images from the period Patek catalog.  Despite much searching, I was unable to determine whether or not it might be original.

During the auction we researched the model and based on the movement serial number determined it was produced from 1940-1945, with this one likely in 1940.  Listings for 5 matching items on Chrono24 were priced from $10,000 to $19,000, and the auction stood at $2200 with 2 days to go.  We judged that many people would not want to risk investing in a watch with a bad movement, but I thought I would have a better chance than most to recover a reasonable price.  In the end, we decided to go for it and won the auction at $4810 plus tax and fees.  That weekend we drove the EBTH in Cincinnati to pick up the watch instead of having it shipped.

Once at home, I inspected it under the microscope looking for flaws.  The case, dial, crown, and hands still looked excellent with very few scratches at all and no blemishes on the dial.  Overall, amazing for an 83-year old watch.  The strap and buckles were okay, but we would likely replace it anyway.  

The one puzzling part was the crystal.  Under examination I could see the face of the crystal was perfectly flat with squared, sharp edges and vertical sides. The underside, however, was concave, distorting (shrinking) any image seen through the crystal.  No other online image of a Top Hat appeared to have this shape of crystal.  Also, the material felt like glass or possibly sapphire, but definitely was not acrylic or other plastic as I understood the original model was.

I measured the crystal to see if I could find a close match from the sources I had identified back when I was working on the Hamilton Myron and the pendant watch.  That's when I made a mistake -- I used my digital calipers to measure the outline of the crystal while mounted in the case, and the stainless steel jaws of the calipers scratched the very soft 18k solid gold of the watch case.  

That was frustrating and led me down a path of researching how to polish scratches out of gold.  It also led me to order a new digital caliper with plastic jaws.

I researched replacement crystals and found that G-S has an exact match acrylic model CX770 with cylindrical profile and correct dimensions (21.6 x 19.5 mm) 

The price for the crystal itself is only $12, but for an additional $25 plus shipping Crystal-fit will install it.  I haven't yet decided which I want to do.  I have replaced crystals twice before on vintage Hamiltons, and it was not that difficult.

To try and diagnose why the movement was not running, I removed the balance with the intent of reinstalling it correctly engaging the pallet fork.  However when I pulled it it was obvious that there was no power reaching the escape wheel.  I let down the mainspring power using the curved slot access to the click mechanism, and in doing so the crown turned only a couple of rotations.  This suggests that the mainspring is bound up or locked, which could be the cause of lack of power to the escapement.

Another issue I noticed with the watch is that when pulling out the crown, sometimes it will pop back in to the winding position.  Initially, I assumed it was due to the gunk built up in the keyless works, but when inspecting I noticed one of the two screws securing the detent spring to the main plate is missing (see arrow).   

I'm hoping I can repurpose a screw from one of the vintage Hamilton 980 or 75 size parts movements I have on hand.  The screw head is 0.8 mm, and some of the Hamilton screws are the same diameter, but I don't know if the thread and length match.

I ordered a replacement crystal from Crystalfit.com for $12 and a new mainspring from eBay for $35.  I'm thinking that I will go ahead and try to service the movement and refurbish the watch myself.  Through Patek, the service alone would be $900, not including parts, as I understand.  A Patek strap is $280 for calfskin or $475 for alligator, both without a buckle.  I can get a new Patek branded alligator strap on eBay for $250-300.  An 18k rose gold 14 mm buckle is listed at  $499, which is probably worth it.  Ofrei has a non-Patek 18k rose gold buckle for $340, and on eBay there are rose gold plated buckles for as low at $36.