For a time in the 1930s, both the Gibson Super 400 and the L-5 models were available with a thick or a thin top.
L-5 serial number 91774, a 16-inch model that was shipped in 1935, appears to be part of a batch of five similar instruments that were produced in October 1934, all of which are described in Gibson’s shipping ledgers as “thick top, old style” instruments.
Author Tom Van Hoose mentions this on page 10 of his book: ‘The Gibson Super 400’, where he states: ‘The difference in thickness between the two tops was approximately 1/16th of an inch, and the thin top version had a somewhat lower, thinner bridge base than the thick top version”.
The choice of top thickness may have also been option in the case of other fully-carved Gibson archtops like the L-12 and the L10.
So, did the terms ‘thick’ and ‘thin’ refer to the actual thickness of the finished top or the thickness of the blank from which it was carved? And was this part of an internal factory experiment, or could a guitar be ordered from Gibson with a choice of a thick or thin top? If the latter is the case, was the top thickness advertised as an option in any Gibson literature?
Vintage guitar dealer John Stewart (myjazzhome.com) comments: “I have seen large differences in the actual thickness of the wood when viewed through the f-hole, so my assumption has always been that the billets were the same with some carved thinner than others.”
Stewart adds: “Andre Duchossoir (author of ‘Gibson Electrics – The Classic Years’) suggested that the billets themselves might have been different sizes: I believe it was a part of large-scale experimentation in the ‘30s. I don’t recall it mentioned in catalogues, but it was a well-known ‘thing’ among older players.”
I’d have thought thick tops were for heavy rhythm and thin tops for single note style, but what do I know?