Buy one these gadgets from screwfix, it has a sleeve that slides over the screw.Brilliant if working up a ladder or driving in slotted heads as it stops the slippage mentioned. [url]http://www.awin1.com/awclick.php?mid=1228&id=61071&p=http://www.screwfix.com/prods/14854/Screwdriver-Bits/Bit-...