I managed to get one stuck slot.It grubscrew out by getting a small self tapping cap screw, putting a dab of superglue on the tip and screwing it in as hard as I could to the grubscrew. This was after I had tried everything I could think of, I was gob smacked when it worked. Since then I have redrilled and tapped all my slot.it wheels and gears to the same size as NSR