There is an article about the Piet Heil helical dial in BSS 92.2 by Alan Mills. (I have a small version of the helical dial which is also mentioned) There was a follow-up article in BSS 95.1 by the inventive John Moir. Following John's instructions, I had no problem making one using, at his suggestion, a strip cut from a piece of plastic gas main, and a strip of 3cm wide elastic stolen from my wife's underwear (don't tell her)
Mike [EMAIL PROTECTED] 53.37N 3.02W Chester, UK
