There was a post years ago, a gent had made a jig to hold a flint, to grind off the high back fints, to make them flatter for better use in the "hammer" jaws.
I think the grinder machine was a wet tile saw, and made the saw fence holder thing to slide back and forth.
With that being said, a suitable holder for the flint, like a dop stick like they use in lapidary work, could be used to craft a cut flint, or reduce a larger to a desired size.
Have been looking into this for a little while, as I'm having difficulty in aquireing flints easily, and crafting out of other than knapable flint/chert seems a bit better way to go.
