Hi
I have a Hamilton #6 case with a front bezel that doesn't screw down tight to the case without exerting quite a bit of force.

I thought it might be hitting the dial so I removed the movement but had the same results.

It starts easily and screws on smoothly but stops short of the body. If I use a rubber ball or rubber case opener I can get it to nearly screw downs all the way but does take quite a bit of effort. It doesn't appear to have any damage to the thread on either the bezel or case.

Can anyone recommend a method that would free up the resistance needed to close this bezel tight to the case without causing any damage.

Thanks in advance
Rick

First check the serial number (may be roman numerals on the bezel) for the case and bezel.

If they match, then there must be a burr or deformation that is interfering. That is where small de-burring tools and jeweler's files come into play. A real jeweler (not an tenant of a shopping mall bling shop) can usually clean it up so it works.

forcing it will only make it worse.

David
the numbers do not appear to match

Regards
Rick

Rick,

Can you shoot a couple pictures... One of the markings on the bezel and the case body/back...

If they are correct and otherwise look to be in good condition... check for out of round. Any indication the body or cover has been dropped... this does not always show up as an obvious deformation, but sometimes is more of a distortion in the true circle.

From there, I use old fashioned tooth paste, the paste type that actually feels scratchy when you rub it between your fingers... it has some form of pumas in it that can act as a lapping compound on case threads.

Put a little on the threads and work the bezel back and forth while you watch your favorite show on the tube... if it gets sticky or dry... just sprinkle a bit of water on it and keep going.

I run it down until it gets snug... then work that spot for a couple dozen back and forths... then try to get another 1/8 or turn out of it and do another dozen or so back and forths... then another 1/8 turn... repeat as necessary...

If it is a burr or nick... sometimes the thing will polish out and all of a sudden it screws all the way on without any further work...

Paul
I will post a couple of pictures latter on.

On occasions I've found it a little difficult to determine the Roman numerical numbers without knowing what the actual number should be. I've found that "v" doesn't come to a point making it look like 2 single slightly slanted lines and I've actually found myself reading the numbers upside down. I had a friend of mine looks at the numbers yesterday and be believes the numbers aren't a match either.

If the numbers don't match why wouldn't the bezel screw on anyway. Please excuse my ignorance but wouldn't any bezel from a #6 case screw on similar to any nut of proper size screw onto a bolt of the same size.
Rick

Richard,

You can also go to the auto parts store and get some valve grinding compound. A small amount on the threads and working the bezel might be enough to clean it up.

Richard, sadly the quality control for thread pitch and thread standardization of matching case threads was non-existent at case makers until after WWII.

It seems that each watch case was hand-fitted, or possibly double-threaded so that the lead angle of the threads were the same.

My experience with these case parts is that the case makers case threads would probably drift around so much that they probably had a lot of re-work to do to get any given amount of them finished.

Certainly case quality assurance was the opposite of watch maker's movement quality.

If you have mis-matching case part numbers, and it tightens up, the pitch angle is probably the cause.

I have on that gives me fits also all numbers
match(Burlington case).Put the bezel on the back
and the back on the front both screw down tight.Put them where they belong and the back will
only tighten down about 80%.Have tried valve grinding compound and it helped some.Every once in a while I try the compound again.Maybe some day
I'll get it!
Roger

Thank you Joe Straub for your suggestion. I've finally gotten the bezel to screw down fully. Joe recommended that I take a needle and chase the threads. They looked clean to me with a 4x loupe but once I started to run the needle along the threads on the bezel I could feel some resistance. As I kept working that area I could feel little pieces give way. I believe that when the crystal got replaced some glue got onto the threads. Being a clear substance could have been why I didn't see it or it could be just my old eyes. Anyway, after cleaning the threads and working the bezel back and forth it now screws down smoothly for about 95% and the last 5% offers up some resistance but does seat tight. I'm confident that with a little more effort I will get it to screw on smoothly all the way.