# M-Series: No O-Ring On Stem Tube?



## Chromejob (Jul 28, 2006)

The second hand M5 I recently purchased had a really grind-y feeling screwing down the crown. Suggestions included dirt in the threads, cross-threaded at one time, or.... I felt it carefully, and couldnt' determine any cross-threading.

Pulling the crown to the hack / second stop and examining with jeweler's glasses, I could see dirt + lube or some kind in the threads. I used Oral-B straight interdental brushes (which are smaller than the exposed tube) to carefully clean out the threads, then used the twisted wire base of one of these to apply a tiny amount of sideburn trimmer oil (similar to sewing machine oil) to the threads and let it trickle down towards the case for a moment before gently screwing down the crown again. Dirt and "grinding" problem taken care of.

But examining the crown, I see that it overhangs the back of the case a bit, exposing the tube within it. I presume that's how some dirt was introduced over time.

















Looking at other dive watches, many have crowns that screw down over the stem tube completely (front and back) and some stem tubes incorporate an o-ring at the base of the tube, to double-protect with the gasket inside the crown.










(Reusing Andy The Squirrel's pic from the R**** Sub-alike thread)

Q: Do the M-series cases have NO o-ring on the tube at all? (Or someone left if off on this watch during maintenance.) If so, what do you do to protect the stem tube (outer threads) from dirt and other contaminants?

TIA.


----------



## Drum2000 (Apr 2, 2010)

I'm sorry that I don't have the answer to your question but I have to say "Well spotted David Spalding"!

I like the way that you resolved the dirt issue as well. AND you eat Korean food! Fantastic!


----------



## Chromejob (Jul 28, 2006)

Drum2000 said:


> I like the way that you resolved the dirt issue as well. AND you eat Korean food! Fantastic!


*Thank you, sir.* :hi:


----------



## spankone (Sep 17, 2008)

mine has no o-ring


----------



## Chromejob (Jul 28, 2006)

I just received another O&W, no o-ring, and the stem tube is a bit shorter. :huh: And even more dirt about the base, so out come the teeny tiny cleaning brushes again....


----------

