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Author Message   Glenn Tinkerer Username: Glenn Post Number: 894 Registered: 07-2006 Rating: N/A Votes: 0 Posted on Sunday, January 23, 2011 - 05:40 pm:    You must use a screwdriver with a large handgrip. If you are using a driver that has an integral grip/blade, the diameter will be way too small to offer enough purchase - the grip diameter on integral drivers is chosen so that one does not over torque the screws on tightening down. Unfortunately the mount screws on the nFD lenses were torqued down using a power tool, thus they are very! tight. Also make sure the screwdriver really fits the screw +head. Sometimes the application of a little heat can help. Use a small electric soldering iron, allow to fully heat up and place the bit on the stainless steel mount ring over the location of each of the tapped holes in turn. Heat for 30/40secs and immediately try and remove the screw that is located in the heated location.