List, I have made this same gap repair with great success. I first cover the flange area on the plate with clear, wide packing tape. Its thin so I can get a really close impression. I press it in place and work out and wrinkles. West System epoxy mixed with Micro Fibers makes a very strong gap filler and bonds well with the pinblock material. Mix to the consistency of peanut butter, apply it to the flange and clap into position making sure of proper location with several of the screws in the block. Next day remove the pinblock, remove tape, clean the edges with a file and fill in any tape wrinkles that might of occurred with more epoxy.
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