Al, a friend and coworker had a "Panerai" replica he bought somewhere. He was having a problem with the setting mechanism, and he had asked me if I could fix it. While trying to do that I broke the winding stem off in crown threads. Though it was an inexpensive watch, it was no longer usable, and I felt bad for Al and wanted to make it right. Though this watch has the same features as the Panerai Luminor Power Reserve PAM 090 model, but the Swiss maker was never produced with a white dial.
In the photo above, one can see the gap between the crown and stem where it broke.
The repair presented three main challenges I had not faced before: 1) how to remove a Panerai-style case back which has a 12-sided gripping surface around the perimeter, 2) how to find a replacement winding stem, and 3) how to find a compatible crown or alternatively, remove the broken stem thread section from the threaded crown hole.
Winding stems are specific to movement design or "caliber". This movement is of Asian manufacture but had no markings to lead to a parts catalog or compatible part. The unique feature of the movement was the 4:30 power reserve subdial. After massive googling and brute-force visual scanning of hundreds of online images, I found the correct movement model, the ST/TY2530 shown here.
Allwatchparts.com sells the whole movement for $42.95, but I only needed the winding stem (below). I was able to order just the stem from Otto Frei for just $4.00.
To open the case back, I could have purchased a special tool from eBay for about $30, but with no other use for the tool, that seemed like a bad investment. I was able to use a small bench top vise to grab opposite flats of the case back to loosen it.
Despite lots more googling, I was unable to find a replacement crown, so I started looking for a way to remove a broken stem.
I found this Omega forum post detailing how a broken stem can be essentially dissolved out of a crown by soaking it in a solution of alum and water. The crown is stainless steel and corrosion resistant, but the mild steel stem is not. There was nothing to lose except a couple of bucks for a can of alum (used for home canning) and time. I soaked it in a Pyrex dish and checked it every day to see if there was any sign of it corroding away.
After about 4 days, the remainder of the stem had turned black, and I used a small screwdriver to scrape out the debris and I was in business!
From there, I was able to give everything a good cleaning, replace the movement in the case, adjust and regulate the timing and get it back to Al for more wrist time.
