Seems I didn’t post my MKII and MKIII Rockshells…

…on the main site. Outrageous!

The Rockshell MKII

Launched in August 1971, with an MST 482 (modified ETA 2630) as the fully in-house MST522 calibre was not yet in production, and the existing MST471 was not available with a Day-Date function. Shown below is the red dial version of this watch.

This was was probably the desk-diver version of the range, as we will see later the MKIII is much more a true diver’s watch. None-the-less, this watch features a compressor case 100% waterproof up to 200 m., a sloping easy-read housing in high grade saltwater resistant stainless steel with hardened anti-reflective mineral crystal with tritium to the hands and markers.

Here are some more photos (the schmutz is gooey gasket)

Note the plain bracelet clasp


The white stuff on the dial is some of the white lines from the crystal, it will brush off when I service the watch. I am really happy with the condition of this one, as often the inner bezel is quite degraded. Win

Next up – the Rockshell MKIII, Electronic

This one is near mint – I would almost suggest NOS, as there is not a trace of wear on the strap (the links are tight as new) or case – however it didn’t come with box or papers.

Also launched in August 1971, with an MST 916 (ESA 9154 Dynatron) – this was a true diver’s watch, featuring 100% waterproof up to 200 m., sloping housing in saltwater resistant stainless steel, with a hardened anti-reflective mineral crystal, dial with raised hour markers and hands in tritium, a large adjustable graduated internal bezel for dive times…

…and the heavier duty strap included an additional clip to expand the bracelet when wearing a wetsuit, plus a clasp lock and the clasp itself is increased in size from 17mm to 20mm.

Wrist shot

Compressor case construction

Fathom Dive Magazine Advert

Wearing it

So, what’s it like to wear. Heavy. Very heavy. But, wrist presence plus. And, that sloping angle, on a watch this thick is great, it makes it much more comfortable to wear. Love it.

Size: 46mm without crown(s) and 160 grams (incl. bracelet).

Update: My Roamer Diver Collection

Also, a little update on my Roamer Diver collection, all on the correct factory straps:

Left to right, early, mid and late Stingray S, Stingray Chrono (Valjoux 72) and the two Rockshells in this post.

Actually there is one more to post, a Seth-Thomas branded version of the Pasadena Valjoux 7734 powered chronograph.

Automatic Roamers

This article is a draft. I will continue to work on it.

The first commercially marketed automatic wristwatches attributed to John Harwood (1894-1965), an English watch maker, manufactured in conjuction with A.Schild (AS), Blancpain and Fortis and was exhibited at the 1926 Basel Fair. This started a rush of invention, with all manner of automatic winding mechanisms, including the Rolls in 1930, the Wig-Wag in 1931, the Glycine in 1931, the Autowrist in 1931, Rolex Perpetual in 1931 (the first 306 degree rotor), the Frey Perpetual in 1932, the Mimomatic pumpwind in 1932, the Aster in 1933 and the Pierce in 1933. One can add to this well known list, Roamer in 1933.

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Balls of Ruby

The gears in a modern automatic winding movement operate such that whichever direction the rotor is spinning in, the rotational effort will be translated into winding of the mainspring. While the arrangement of the gears is simple enough, the real problem is twofold, firstly to do so efficiently, so even small wrist movements will wind the watch, and secondly to do it in such a way that is long lasting. Many early full rotor designs were not the efficient winders we take for granted these days. Also, any time you look in an old watchmakers drawers – you’ll see countless older ETA, AS and even the occasional Eterna or similar design, movements, with their pawl wheels missing and their automatic train holes oval.

MST 471

The movement we’re looking at in this post is the MST 436/470 Roamer 44 jewel automatic from the early 1960s, in which Roamer, decided to do something much more interesting…
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44 Rubies

The MST 436/470 (437/471 with date) was a prestige movement family designed and produced by Roamer in from 1964 in a no expense spared effort to move the brand upmarket. It worked too, because the movement was innovative, robust and long lived. It featured in the top of the line Mustangs and Stingrays for almost a decade. With 44 jewels, the best versions of these movements have the most jewels (that I know of) that are really functional.

While not all 44 jewels are absolutely critical for good timekeeping, and some English old timers back in the 1800s would have argued that 7 jewels in a lever escapement are all that are needed, the added jewels do add to the longevity of the precision of a movement – that is, the length of time it will continue to work within design parameters. Lets look at where all these jewels live in the movement.

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