*I have a garden shredder. If I wish to dismantle it (say when it jams) I find I cannot unfasten the screws, because they are of a strange type At the lip of the recess in the head the shape is hexagonal but this develops into a hemisphere within a short distance. What is this type of screw called and where to I get the tool which will offer purchase on the screws?
If you are describing an allen head screw that has a bump in the middle of the hole to keep you from inserting a standard allen wrench, these are called tamper proof screws (as the generic name for many different designs). You can purchase a set o bits that cover many of these designs. (typical link below). Making sure you get the right kind and size in a set is the hard part, unless you can find a set at a hardware store. -- Regards, John Popelish
Not sure which this is, although it sounds like a hex head, but hardware stores stock lots of different screwdrivers for lots of different heads. .
problematic step. look on to yahoo or google. that will help!
