This little one button chronograph came in for a service and crystal change earlier in the year, It’s a Seiko reference 5719-8992. As you can see it’s actually out of the case and in a movement holder in this shot.

These little one button chronographs are interesting watches in Seikos development. They marked the first commercial chronograph that Seiko developed for the mass market, whilst Seiko had made a chronograph model back in the forties it wasn’t available to the general public as all production was destined for the Japanese military forces. The 5719 and 5717’s were brought to market on the back of the 1964 summer olympic games in Tokyo where Seiko were the official timekeepers. The early ones had an olympic torch stamped or etched on the caseback, but later ones can be seen with the seahorse design or the standard horseshoe type. There are also versions with the Asian games torch and the Military anchor so there are quite a few variants to choose from. They were priced at about 75% of the cost the World Time watch as can be seen in this period advert from an American newspaper. This advert also shows the bracelet that these watches would originally have come on, both were the same design but they came in an 18mm lug width for the 5719 and 19mm for the World Time.

There are two basic models, the 5719 pictured on the left in the image below and the 5717 pictured middle and right.

The 5719 has the chronograph track printed on the dial as opposed to being printed on the chapter ring like the 5717. The 5719 also has a luminous filled hour and minute hand and luminous dots by the indicies. The 5717 doesn’t have these luminous features but does have a date display. These watches came in many varieties, you could have a black or silver dial, a stainless steel rotating bezel or a black bakelite one which tended to be replaced at service time with the harder wearing stainless steel version. As a consequence of this examples with a bakelite bezel in good condition are few and far between, I’ve seen ones with the bakelite worn almost smooth, they should have the same ridged shape as the stainless steel bezels pictured above! There was also a version that had a bezel with a printed insert as with the watch featured.

Being the 5719 model underneath the dial is unencumbered with date wheels and calendar mechanisms, as such it looks quite clean.

On the reverse side you can see the chronograph mechanism with it’s column wheel and crash type chronograph drive.

Remove the bridge and you can see the chronograph centre wheels heart cam and reset lever.

The watch was fully stripped ready for cleaning and inspection.

A new mainspring was fitted.

And the whole movement was reassembled and recased. The picture below shows the movement off beautifully.

With the new crystal fitted the job was done. This example is one of the scarcer variants with it’s printed insert and black dial. To operate one of these it has the usual start-stop-reset sequence on the button, to count anything greater than one minute you need to turn the bezel so the triangle is adjacent to the minute hand and you can then read the elapsed minutes. Simple but effective!