Leave it to knifemakers to be able to make a controversy out of almost any subject . . . This again supports my theory of the importance of alcohol in the creative process!!!
I am amazed to find that some folks, including some makers, suggest that an integral sub-hilt is nothing more than a finger groove!!!
Wow! You learn something new everyday!! Now, I am left to ponder whether these same folks would consider any forward integral guard/hilt to be nothing more than a "speed bump" between the handle and blade???
The term "sub-hilt" suggests a secondary hilt. To declare or insinuate that an integral sub-hilt does not qualify as a "true" subhilt is to, likewise say that an integral forward guard or hilt does not qualify as a "true" guard or hilt. That would be, by most people's definition, ridiculous.
Both hilts, forward and sub, are designed around a particular function, whether it be the forward hilt, designed to stop the hand from sliding forward onto the blade, or whether it be the sub-hilt, designed to give added control and supply the finger behind the forward hilt a base upon which to pull when retrieving the blade.
Simply adding a pair of either nickel silver, stainless steel, or brass bolsters pinned or soldered to the sides of the tang or incorporating a single milled piece of metal in this area of the handle does not make the sub-hilt any more or less functional than an integral design. Nor does it make it any more or less of a true sub-hilt.
If the term were "sub-bolster" then I would agree that it would be necessary to add a secondary material to the handle. The term "sub-hilt" does not suggest that.
I suppose that what constitutes a "hilt" or "guard" is open to speculation and interpretation. However, if you choose to define the term, as I do, by its functionality, then integral guards and sub-hilts do exist. . . Yes Virginia, integral guards do exist!
I have made both integral and non-integral types and although the level of difficulty can vary, neither is more functional than the other.
I would agree that it could be considered as a mere "finger groove" if there were not a sufficient amount of "hilt" to supply the added control of a "true" sub-hilt. But as you can see in the pic of the Busse knife, there is sufficient "hilt" for these purposes.
Yours in integral sub-hilts,
Jerry