There’s been a lot of talk recently about drift pins, and making sinusoidal
stakes for anticlastic raising. Within the last year (or so), Lapidary
Journal ran a two part workshop article about how to make and use such a
stake. The author of the article also provided the prices for a finished
stake and an unfinished stake (a machine tapered steel rod). For those of
you running around looking for materials, it might be worth investigating.