Screw-on Bezels and Backs

[ctonyzee]

Hi All....New Kid On the Block looking for
advice again. I have several 16-18S cases.
The bezels and backs are difficult to screw
on and off....is there any way to restore
the threads on these cases?....Is there a
special tool required?...Are these threads
Metric or English...Thanks...

[ctonyzee]

Hi All....New Kid On the Block looking for
advice again. I have several 16-18S cases.
The bezels and backs are difficult to screw
on and off....is there any way to restore
the threads on these cases?....Is there a
special tool required?...Are these threads
Metric or English...Thanks...

[Kent]

ctonyzee:

The first step is to inspect serial numbers of the three parts. In this day and age, a number of cases have had their parts pulled out of a scrap bin so as to choose the parts with the least damage. If the parts are from different cases, the discussion below won't apply.

The back is easy, the S/N is pretty obvious. It may also be stamped on the center ring and on the bezel. More likely, the last four digits will be scratched on in Roman numerals. For the bezel, it'll inside the curved section.

Of course, before you begin, remove the movemetn from the case. Look at the threads carefully. If they're dirty, clean them out with a solvent. Afterwards, wrap a polishing cloth over your fingernail and run it through the threads.

If any burrs are sticking up, try pressing them down with the flat of a small screwdriver. If there is a noticeable bump at the burr, try shaving it down with a very sharp knife.

If the threads are actually bent out of shape (its been know to happen), you'll have to decide if its worth risking making it worse: "Just how bad was it to screw on and off anyway." You can try straightening the bent threads with the flat of a small screwdriver.

If all this doesn't help, somebody more advanced than I am will have to help.

Good luck,
Kent

[BrianC]

When all else fails, I take and put a dab of automobile valve grinding paste on the case threads and work the case back or bezel, back and forth a little at a time, each time trying to screw it on a little further. Try it, it works. Make sure you clean the case good after your done.
Brian C.

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[This message has been edited by BrianC (edited 07-01-2001).]

[Steve Maddox]

Hi guys,

I don't know about the valve grinding paste -- I'd be as afraid of that as a lion. It seems to me that this would be like pouring sand into the threads, and the particles would become imbedded in the metal and never come out!

Here is one of the oldest and best watchmaker's tricks I know. Obtain a small resealable bottle, some bee's wax, some naphtha (liquid cigarette lighter fluid) and some oil (clock oil, gun oil, motor oil, it doesn't really matter). Scrape the bee's wax with a knife so as to cut it into shavings, and place the shavings into the bottle. The bees wax will easily dissolve in naphtha, and enough naphtha should be added so as to enable you to stir the bee's wax into a thick "grease." In order to keep it from drying up rapidly, add about 10% oil to the solution. You have now created one of the finest "anti seize" compounds known to man!

While just pure oil will often allow metal to grab and "gaul" up, bee's wax has an almost unique ability to prevent this. When it is applied to case threads, they can easily be worked back into shape just by screwing the backs and bezels on and off several times (unless the threads are already severely mangled).

Hope this helps!



------------------
Steve Maddox
VP, NAWCC Chapter #62
North Little Rock, Arkansas

[Larry Jones 98326]

As Kent implies, often this type of problem is caused by "bent" threads. Generally, with the back and bezel off, sighting across the case while rotating will reveal an area where a small edge dent has deformed the threads. If you're inclined to try to remove the dent, do so before working on the threads.

I use a thread file to file down the binding side of the deformed threads. I don't know if these files are still available new, all I have came from watchmaker's estates. With patience, you can almost always improve the problem, but almost never eliminate it.

I have used the valve grinding compound with good success, but the fine compound of a coarse - fine set is the best (if you can still find it). One thing to remember is that the abrasive takes up clearance in the threads, so you need to stop before you can screw the back or bezel all the way down easily or you will remove too much material. If you overdo this, the threads will be stripped and the case will be scrap or junk. When you're done, clean, clean, clean (NOT in the watch cleaner. aggggggggghhhhhhhh!!!!!), then lube as per Steve's suggestions. Beekeepers usually have beeswax.

Good luck, practice on a junk case is always advisable.

Larry


[This message has been edited by Larry Jones 98326 (edited 07-03-2001).]

[ctonyzee]

Well...I'm impressed...thank you all for sharing your expert advice...I'll try these
remedies this week.