A way to measure top thickness of a closed box

[Dave Bagwill]

Okay, these few little things made a big difference. I want to emphasize that the whole thing has to be solid. No jiggle, much as we all may like it.

I shortened the aluminum bar in the lower jaw by 2" and drilled a hole for the rivet, pounded it in, and shortened the CF strip to meet the middle of the rivet exactly.

Then I took off the wood in the yellow picture above, but did not cut into the aluminum bar, and then rounded off the corners so when the gauge is against the back of the hole, only the bar is touching, for maximum clearance.

Also rounded the corners of the wood right down to the aluminum on the opposite side.
These little adjustments gave me pretty much full coverage of the rim from the waist down to down close to the endbock. So I'm happy - one less area of unknown information is now available.
Now if I can just take advantage of the fact. :-)

[Dave Bagwill]

These are the results of the OM body I am working on. The gauge, though inexpensive, returns to zero just right. The cf does not scratch - I rounded it of course.

Now what do I do? Either sand down the rim or drill using the method Ken shared with us and then measure. Some guys go scary on this, down to .060 close to the kerfing, don't know if I am that brave yet.