This is a Regalis dress watch with an AS 1220/1221 movement. The one thing that immediately jumps out if you look at the movement is the triangular hole in the wheel train bridge. This can be used to inspect or lubricate the bearing jewel of one of the transmission wheels. But if that’s necessary than it probably needs a service anyway and you’ll have to remove the bridge altogether. Or they might have just put it there as decoration.
I’m not a 100% sure which type of shock protection this is but it looks like Monorex or Simrex.
The watch is 31 mm in diameter, so it’s rather small for today’s standards. It’s even a little small for the time period (the late 40s / early 50s) it’s from. Some people would qualify it as a boy’s watch.
It looks like Regalis was a part of Nivada.
The case doesn’t use a traditional case back. Instead, the bezel and the lugs are placed on top of the case back (with the movement, dial, hands, and crystal). It’s secured with 4 screws on the rear of the lugs.
It’s hard to loosen these screws because there is a lot, I repeat…a lot of dirt inside.
Start by removing the power from the mainspring.
Lift the balance and the pallets.
Remove the ratchet wheel and the crown wheel with its shim. Lift the barrel bridge.
Then, take out the wheel train bridge to gain access to the wheel train.
Now you can lift the main barrel, 4th wheel, 3rd wheel, escape wheel, and then remove the center wheel cock.
Now it’s getting interesting because this movement doesn’t have a traditional center wheel. It has a pinion that’s driven directly by the mainspring barrel. Then there are 2 smaller transmission/intermediate wheels to drive the 3rd wheel and continue the train.
Remove these parts and flip the movement to the other side.
Take out the motion works and then the keyless works.
Peg the jewel holes, the pallet stones, and the pallet fork.
Clean all the parts in the watch cleaning machine for 6 minutes a bath.
Start with the center wheel pinion and the 2 transmission wheels and cover those with the center wheel cock.
Replace the main barrel.
Replace the escape wheel, 3rd wheel, the 4th wheel/sweep second wheel, and fit the wheel train bridge.
Then, fit the barrel bridge, the crown wheel, and the ratchet wheel.
Flip the movement over and install the keyless works. Then install the motion works.
Turn the movement around once more and install the pallets and finally, the balance.
With the movement running, you can remove the shock protection endstones to clean and lubricate.
Use an oiler or the tips of a fine pair of tweezers to turn the endstone until one of the feet can be lifted out at the notch.
Clean in One-Dip or similar and lubricate with a tiny bit of Moebius 9010.
Do you own a regalis or a similar watch? Would you wear a 31 mm watch? Let me know in the comments below.