OK, good news and bad news. The good news is the new eccentric spring bar worked AMAZINGLY. Not only was it an absolute breeze to install, the fit was VERY firm and snug (no way it's going to rotate). I just oriented the shimmed side to the bottom of the SEL, pressed it in using the tip of a precision flat blade screwdriver, made sure it was centered on the SEL. Done! Install SEL into watch case like normal, PERFECT.
You might remember from the OP that my first stab at this was stacking layers of very narrow strips of aluminum tape (about 1 mm wide) onto a 1.78 mm spring bar and pressing that in. That approach came out excellent for the bottom SEL, but the top SEL wasn't quite as awesome - failing to achieve a satisfactory level of recess at one of the lugs.
But with the new spring bar I built today, both ends of the SEL appear to be equally recessed and I am VERY happy with the amount of recess compared to before. The top SEL still isn't recessed quite as much as the bottom SEL, but there's nothing that can be done about that other than going down to a 1.5 mm spring bar and I'm not doing that because I find the 1.5 mm spring bars to be too flimsy. The SEL recess at both top lugs is even and deep enough to create enough contrast to make me very happy.
So that's the good news. Now the bad news.
The bad news is this spring bar was a son-of-a-B to make. The time spent to make the jig to machine the capillary tube is a one-time thing so I don't count that. I have the jig now. I can machine as much capillary tube as I need easily.
But cutting off a precise length of the machined capillary tubing (which must be done very carefully as it is SUPER thin and deforms easily) is a tedious process. Then there is the RTV silicone adhesive used to glue the 1.78 mm spring bar into the shell. First, you have to apply it under magnification, using a toothpick, and it still gets EVERYWHERE because you have to hold on to the part you're applying it to somehow. But then you have to somehow hold the two pieces in precise alignment for 5 hours to let the adhesive cure sufficiently for assembly. I chose to use my digital caliper to do that, and it worked very well for the task, but I don't have a dozen digital calipers lying around and making one spring bar every 5 hours seems like a terrible plan.
So...
I need to come up with a way to make these things a little easier to make. They work AWESOME, but they take too damn long to build. I say "they" even though I only made one so far and used it to replace the aluminum-tape-stacked spring bar in the top SEL from the first attempt. The bottom SEL still has the spring bar from the first attempt in it.
One option for making this easier to make would be if I could fashion up some sort of gluing jig that I could just set the 1.78 mm spring bar in, then fill a shell with RTV, and lay it in on top of the spring bar, and then have some sort of top half that holds everything in proper alignment. I think making such a jig might be a royal pain in the butt - and I'm not even that sure how well it would work. If the two halves aren't glued together and held in precise alignment I don't think the finished product would produce a satisfactory result.
That said, I have another idea that would still use the machined capillary tubing along with a 1.78 mm spring bar, but would be A LOT easier to assemble. I'm going to try that first and see how it goes.
OK, bad news aside, pics of the outcome with
this design of the spring bar are needed, so here goes.
Here is what my top SEL fitment looked like
before:
And here is what it looks like
now:
That's all for now. More when I have something else to report.
P.S. No, I did not take a picture of the new eccentric spring bar. It was basically impossible to photograph and be able to see any detail. The CAD drawing earlier in this topic gives the best idea of how it is constructed. The only difference between the CAD drawing and how it's really done is the void between the shell and the 1.78 mm spring bar is empty in the CAD drawing whereas in the actual assembled article that void is filled with black silicone RTV adhesive.