Bill Gottesman contributed: > >I have seen advertisements for pneumatic turbine "pencils" that rotate at >400,000 RPMs, and take 1/16" bits. They claim to cut as effortlessly as >writing with a pencil. Any experience out there using these devices on the >different types of stone?
It sounds like my dentist's 'airotor' handpiece - the reason why dentists are prone to high frequency hearing loss it seems - in addition to high levels of mercury in the toenails! "Is there no limit to this man's useless knowledge!?" Seriously though, put that together with the 'UniCut2' jig I wrote about earlier and we might have a very practical device for dial makers. I was wandering around a local churchyard cemetary today, weary with milling stainless steel and inspired by the discussion on the durability of various types of stone (any excuse to stop tedious work). This cemetary is on a clifftop beset by wind, salt and windblown sand. Some of the headstones are several centuries old and I notices a most curious phenomenon. Some sandstone headstones had all of the 'background' around the carved lettering worn away but the carved lettering remained, albeit heavily worn, as 'islands' standing proud by as much as an inch. How did the action of carving the letters reduce the surrounding areas' susceptibility to erosion? Weird! Tony Moss. -
