odd size 703 tube?

[stilty]

Correct me if I'm wrong, but I seem to recall a topic a long time ago about a batch of genuine Rolex 703 tubes that had an odd-ball thread size. They were larger then the standard tubes. Apparently, they were made by Rolex to install in cases that had worn threads in the case. So the case was retapped, but then a larger tube was required.

I recall that a few people bought these tubes, but were unable to fit them because they were too big.

Does anyone have one of these tubes?

[JoJo35]

RG told me he had problem fitting a 702 tube because of the threads being an different size, but I've never heard of a 703 tube with a larger circumference. Perhaps the best place to confirm would be on VRF or TZ? Maybe RG would know.

[ubiquitous]

I seem to recall these as being a sort of hit or miss item as I don't believe the tube diameters are clearly identified on the blister pack.

I can ask a few of my sources if they have any in hand... It will likely come down to eye balling one against the other, and that's provided they have some mixed into their stock.

[stilty]

Thanks guys. Please PM or email me if you do find anything out.

best regards.

[Logan]

Yes there are two distinct sizes of thread. I do have one or two of these tubes still.

[Logan]

If you do a search for "ponycar" you should find the old posts on this topic. Ponycar was the ebay dealer who sold these tubes a few years back.

From memory the standard thread is a 3mm x 3.5 standard metric thread and measures 2.96mm on the tube itself. The over size is a custom thread and measures 3.04mm on the tube.

[alligoat]

I was looking at taps this afternoon. If 3.0mm x .35 is the standard, the next size larger is 3.5mm x .35. Then you'd use a 3.15mm drill bit to drill the hole and then tap it. With the 3mm x .35 you drill the hole with the 2.65mm drill bit- subtract the thread pitch from the diameter of the tap- 3.00mm - .35mm = 2.65mm.

This is all conjecture, but I can't see where Rolex would be using a non-standard sized tap.

[Logan]

Its definitely a custom size tap, you can't buy one trust me. Its only about .08mm larger then the standard size so definitly not a 3.5mm.

Remember these tubes are only used by Rolex to fit old case's with worn or damaged threads. I guess busted tubes account for a fair proportion of these.

I have both the ponycar tube and the regular thread type here so the measurements are taken direct from them.

[stilty]

Thanks for the info guys. Very much appreciated.

so is there a way to tap the case in order to fit the larger tube? I guess I would have to get a custom tap made?

[Logan]

Its only a little larger, so I guess you could deliberately make a sloppy thread (hand hold both parts, wriggle the tap a bit while turning) Someone ages back shrunk the tube with nitrogen but thats a bit extreme.. and risky to you and the watch.

Another option is to drill the case, and glue the tube in place with JB Weld or similar. This is actually the most waterproof as you'll struggle to get the threads and o-ring seat accurate enough to take serious pressure.

[alligoat]

Sounds to me like a 3.10mm x .35 tap would work- might not even need to drill the hole.