Hi All, I have a problem with a bolt on my car. It was a Torx type star headed 10mm bolt which is supposed to be tightened to a torque of 15 ft.lbs and is one of three holding the pulley onto the power steering pump,. When I tried to undo it the torx tool simply ripped the stars off leaving a round head. Just to make it worse it is typically in a awkward place to get too and part of the design of these beasts is that they flare out towards the base so forming their own washer. So I am now left with a cone shaped disaster zone. Using a Dremel type slitting disc I formed a slot in the remaining head and so far using screw driver blades that fit into a 1/4" drive socket have sheared off four blades. I even tried heating it up using a Micro blowlamp. From this it seems that it does not look as though it is ever going to shift and so have hatched another plan. I intend to use a Diamond Core drill, as used for drilling holes in very hard marble tiles etc. I have used these when installing bathrooms. What I hope to do is place the core drill over the pointed head of the bolt and grind my way down to the pully face hopefully turning the bolt head into a stud. Thus I hope at least to be able get the pulley off. I was hoping to put a thread on the resulting stud and then put a nut onto it but there will not be sufficient clearance to get a die down it. The pulley therefore is going to have just be held on by the remaining two bolts with the stud just taking some of the drive load. The Question is, has anybody any experiance with using Diamond Core Drills to cut steel? Regards Clif MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.