Some idiot (ie. me) decided that it would be splendid idea to have an externally vented extractor fan in the kitchen.
The cooker is on an external wall and so we bought a new hood for it complete with a ducting kit.
Lord Lucan, supplier of all trades to the aristocracy and peasantry alike, said he had the required core-er and appeared ready to do the job.
All went well as first plasterboard then polystyrene and then brick dissapeared easily and were emptied out from the drill-end. Then we approached the outer wall of our sandstone house. Well - we anticpated that the rear wall would be sandstone, like the rest of the building and were a little surprised to find that we were trying to drill through solid granite, which seemed to object to being cored and put up a stiff fight. The main problem was that when the corer had cut it's full depth and could go no further, the central piece of rock was too strong to break off.