Bill's Big Problem
As part of this E-Portfolio, we are to identify one problem we encountered during the build and how it was resolved.
As part of this E-Portfolio, we are to identify one problem we encountered during the build and how it was resolved.
This was a hard one. I made numerous mistakes in this first acoustic guitar build. But one was a whopper.
This was a hard one. I made numerous mistakes in this first acoustic guitar build. But one was a whopper.
A number of mistakes and circumstances cascaded to create a serious cosmetic problem on the back:
A number of mistakes and circumstances cascaded to create a serious cosmetic problem on the back:
- Because of the way the BBT template was oriented on the oversized top and bottom pieces—I matched at the neck and not at the nominal geometric center as I should have done—the nominal 1/4" "rolling quarter" created overhang that should have been present on each end was basically pushed forward to the neck end;
- The side assembly was secured inside the nominal 2" thick and 2" wide BBT mold significantly limiting the visibility of the portion of the sides that extended beyond the mold; and
- The side assembly was attached to the braced bottom in the "bottom down" configuration as demonstrated by the instructors
In the image above, the thick and wide edges of the #3 BBT mold completely overhang the braced bottom/side assembly interface. To see the misaligned (short) braced bottom, one must drop down into an "edge on" point of view.
In the image above, the thick and wide edges of the #3 BBT mold completely overhang the braced bottom/side assembly interface. To see the misaligned (short) braced bottom, one must drop down into an "edge on" point of view.
But this last (missed) opportunity was actually the SECOND opportunity to catch the misalignment...
But this last (missed) opportunity was actually the SECOND opportunity to catch the misalignment...
The first opportunity to catch—and avoid—the misalignment issue was when the bottom (and for that matter, the top) was marked for trimming the bracing (or slotting the kerfing (operation shown).
The first opportunity to catch—and avoid—the misalignment issue was when the bottom (and for that matter, the top) was marked for trimming the bracing (or slotting the kerfing (operation shown).
Unfortunately, these operations were also accomplished with the BBT mold in place thus obscuring the interface of the side assembly with either the bottom or the top.
Unfortunately, these operations were also accomplished with the BBT mold in place thus obscuring the interface of the side assembly with either the bottom or the top.
New Rule:
New Rule:
When measuring the bracing/kerfing for trimming/slotting, PRIOR TO MARKING, hold the braced bottom or top securely against the side assembly/mold and lift up high enough to visually inspect the entire interface to make sure that there is no misalignment; adjust the fit PRIOR to marking.
When measuring the bracing/kerfing for trimming/slotting, PRIOR TO MARKING, hold the braced bottom or top securely against the side assembly/mold and lift up high enough to visually inspect the entire interface to make sure that there is no misalignment; adjust the fit PRIOR to marking.
OK, that rule is a good one for avoiding this particular type of problem in the future. What can be done to fix the existing mess?
OK, that rule is a good one for avoiding this particular type of problem in the future. What can be done to fix the existing mess?
(Hint: The next page is called "Hiding One Mistake")