A drilling question ... is it possible to get Centre drills for the smaller diameter drills .... .07, .05, etc. If so ... where from?
Tim Lee
As a 2mm modeller, I have found that making my own in Silver Steel seems to work (although I have a lathe). A piece of suitable round bar is mounted in the lathe, a 60 degree cone is turned on the end, then the bar is mounted in a vice and filed to reduce the cone to a half cone which is then hardened and finally stoned. Obviously the cone has only a single cutting edge but if the original bar is substantial enough (I usually use c. 3mm upwards) is fine.
I have also used gramophone needles to make a tool that is suitable for making a starting pilot hole for small drills. The end of the needle is stoned to generate a pyramidical shape at the point (i.e. 3 cutting edges). Being quite small, obviously magnification is required (but as I said I'm a 2mm modeller) to ensure that the facets ground on the end are similarly sized and shaped (indicating that the point of the pyramid is central). I have even used these in my lathe tailstock to start a hole that I will drill out to <1mm.
Hope this is useful (and that I am allowed to post)
Ian Smith
