Hi all, I was hoping that that the watchmakers here could help me with my technical question.
I have recently been looking at making my own custom valjoux 7750 watch dial. The watch case that I was going to use is designed to fit a dial that has a 1.5mm tall angled tachymeter rehaut ring that fits snug in a gap under the crystal, besides that the circumference is the same 36mm.
The custom dial that I want to install doesn't have a rehaut and is flat and because of this there will be a 1mm ( empty space) between the top of dial and the bezel ring under the crystal.
I was probably going to install a 1mm clear crystal gasket to fill in that space so the bezel fits snug, but I have noticed that when I install the custom dial, it didn't move because it was held in place by the 2 dial feet and the 2 movement clamps back of the movement.
(If you were to try to push to movement forward or back it would not move in the middle case, as the back of the dial rested flat in the middle case and the clamps on the back of the 7750 movement pulls the dial tight against the fixed middle case ring...... So as the dial can't move forward towards the crystal ).
Now My question is how is the valjoux 7750 movement designed to be clamped in the watch case?
Does the dial have to be pressured from the top( under the crystal) to be secured so it doesn't move forward up towards the crystal?
And are the dial feet strong enough with the 2 small back movement clamps to secure it in the middle case?
Is this the way that most valjoux 7750 dials are held secure in the watch case?
Any answers will be appreciated, cheers

 

I wouldn't rely on the dial screws to hold the movement.

Some 7750s I've seen are held in the midcase by a spring ring and the caseback pressing the movement toward the dial.

Others have a movement ring,



Do some Googling to see what method will suit your case.

 

Thanks for your reply, my watch case design is similar to the way you described how a 7750 is attached to a movement ring,..... except the movement ring is fixed.
The way to install the original bezel for my case is that you .....
First have to attach the dial to the movement,
Second feed the movement through the front of the case,
Third screw the 2 small clamps on back of the movement (as you have highlight).
Forth, press fit the front bezel ring( with crystal fitted ) over the dial.
Finally screw in the case back.
My problem is that the new custom dial has a 1mm gap between the dial and under the bezel.
Should I fill this gap with a clear plastic crystal gasket so as the dial will fit snug and be supported better?
Or could I get away with the 1mm gap because maybe the valjoux 7750 movement was designed to be held in place with only the dial feet and back movement clamps?

 

Can't say that I've seen a front loading case for a 7750 before - where did you get this case?

It would be unusual for the movement to be supported by the dial. Most likely the case is designed so that the lip that is on the main plate of the movement rests on the case when you load the movement in from the front, so it's supported by that lip and not the dial. Then the screws that go into the main plate from the back side secure the movement to the case. If it's like this, then the only issue is cosmetic and that's up to you to decide if you want the gap or not.

You can verify this by installing the movement in the case without the dial mounted, and if it can be screwed in place you are fine from a structural standpoint.

If the movement just "falls" through the case, then that is a problem and it's not a case I would use.

Cheers, Al

 

Just tried the movement without the dial, and your right! The movement is held securely with just the 2 back clamps.

Can't believe that I didn't try that before I posted the question.
Cheers