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This is NOT a "leather" question, but knowing many of you are also involved with other heavy materials and fabrication, I thought I'd ask ... I'm sewing a canvas awning that utilizes snaps to attach to a steel framed roof rack on our expedition van. Problem = I've tried several varieties of self-tapping "screwstuds" and none seem to do the trick! The screwstud will start to bite into the steel but then it seizes and the head either strips or completely spins off. Here's a link to screwstuds I'm using ... http://fasteners.fasnap.com/viewitems/screwstuds/self-drilling-screwstuds Notes: I've used various types of self tapping screws in the past without this issue (i.e., sheet metal roofing screws). Side by side these look identical to these screwstuds, other than they don't have a snap top. Just to rule out the strength of the steel frame, I tried some of my regular self tapping screws on the same metal and had no issue. Also tried predrilling smaller diameter holes into the steel frame and then use the self-tapping screwstuds, still no luck. They bite and then strip or break. I tried a slightly larger drill bit size and the hole ends up too big to provide any grab for the screwstud threads. I even tried "drilling" a hole with the standard self tapping screws that I have, backing out the standard and then screwing in the screwstud. Same issue, either the hole is too large and no bite, or too small and the screwstud seizes. Also each of the above with lubrication (heavy cutting oil), no change. I am using a basic cordless impact driver to set the screws, just like I always have. This really has me stumped! Pictures attached of the screwstuds I'm trying and my roof rack that I'm trying to attach them to. Any thoughts, suggestions, tricks would be appreciated!!