I make no apologies for the fact that the Seiko 62mas is my favourite vintage Japanese dive watch. For me, the case size at 37mm is perfect and the design is a classic. I’ve owned every variant and restored many more of these beauties so when I was offered a case, bezel and dial I thought they would be fine for spares at the least. When it all arrived the case had no tube so was essentially useless and the dial had no feet! The bezel was a nice example though. Well these parts were put in stock and I thought no more about it. As time went by I picked up a spare 6217a movement complete with the case ring and some NOS crowns, stems and crystals. In the mean time I was contacted by a friend of mine who mentioned he was actively looking for a 62mas diver and did I know any for sale? I remember I had this project tucked away so I said if he hadn’t found one by the time this was finished he could take it if he liked. This gave me renewed interest in the project and when I revisited the case I realised I had enough parts for a complete watch if it wasn’t for the missing case tube that had been butchered out. I thought I’d have a go at fitting a generic tube of the correct dimensions, after all I had nothing to lose! I reamed out the hole in the case to the size of a suitable tube, however there were still some rough spots in the hole that I couldn’t remove as the diameter would have ended up too large. Although the tube pressed in nicely I decided to smear some slow curing two part epoxy around the inside of the hole and on the tube to prevent the possibility of any moisture ingress. The pictures start here, I didn’t take any earlier ones because in my mind at that time they were essentially just spare parts!
Here is the new tube in place in the case.
The NOS crown fitted snugly and the NOS crystal was fitted, so far looking very good. The case shape was actually in excellent condition with very little wear or damage evident.
I fitted a new caseback seal and as the crowns seal hadn’t hardened with age and was still lovely and flexible I decided to give it a pressure test to 6bar. Into the chamber the case went and it was pressurised.
Wait fifteen minutes to allow the pressure to build up inside the case if there is a leak anywhere, then submerge it.
Release the pressure and look for bubbles escaping, if there is a leak the pressure inside the case will now escape the way it came in and will be evident by a stream of bubbles which allows you to pinpoint where the leak is. This particular case passed the test perfectly, no leaks at all! This cheered me up immensely, it’s not often these can be made water resistant after all these years.
My attention now turned to the dial, unfortunately the lume was in pretty bad condition and had actually dropped out of the 9 plot (the bezel has an aftermarket insert placed on top in this shot). I selected a decent set of hands and sent them off with the dial to James Hyman who does my relume work.
Once the work was done and I had the dial and hands back I needed to sort out the broken off dial feet on the reverse. I’m not a fan of dial dots, the little self adhesive pads that can be used to hold a dial in place, if it had feet before then it needs a new set fitting!
I have a machine for re-soldering feet back on without damaging the dial finish so the feet stumps were filed shiny and fluxed ready for a new set.
The dial is placed in the machine and copper wire of the correct diameter is used to replace the foot.
Tiny pieces of solder are placed around the joint then a few seconds of current is passed down the wire, this instantly heats it up so the solder flows and a joint is made.
All that remains is to trim to size and dress the end then the other foot can be tackled.
Trim the next one and dress it and there we have it, a repaired dial.
Now the dial was done I could tackle the movement. It was in reasonably good condition with no past butchery evident, just dried out lubricants and grease.
The movement was fully dismantled for cleaning and inspection, the only things needed were a NOS date wheel and an hour wheel ring. The date wheels tend to discolour badly on the 62xx caliber, and the hour wheel ring is essentially a spacer that that takes the place of the 24hour wheel that isn’t used in this model. The 6217a movement was originally designed for the Seikos World Time watch in 1964 and these had a 24hr hand. Even the clutch and date corrector was still in fully working condition and these are a particular weak point of the 62xx calibre.
The mainspring and barrel re-assembled and properly cleaned and lubricated.
The motion work coming together.
The new date wheel and hour wheel ring fitted on the calendar side.
Back together again and ticking away nicely with bags of amplitude.
The dial and handset fitted.
The movement re-cased and ready for closing.
And there she is finished, another one of these iconic divers saved from being parted out. The 62mas is commonly accepted as being the first proper (ISO rated) Japanese dive watch, of course there were the Seiko Silverwaves that came immediately before but these were only rated to 30 and 50m depths. Whilst the Silverwave line provided valuable insight for Seiko about how to go about producing a divers watch, because of the limited depth rating they weren’t seen as serious dive watches.
The beautiful dolphin caseback is still readily visible on this. The ones made before 1967 tend to wear badly for some reason so it’s always nice to see a legible one.