See image for location to manually trim the stud (If i had cut the model there, your printer would not be able to make a satisfactorily strong 'nub') The blade will be very snug. clean the inlet with a knife first. use a small screw driver to work the blade back and forth within the complete slide area. If needed, stand vertical, with blade in tight spot, then heat carefully with flame. plastic will expand and allow freedom of movement within slide channel. steps: 1. Get blade moving safely prior to any assembly. this is a critical safety concern. 2. With blade fully inserted/retracted, push stud through chassis slot and blade slot. the overhanging material on the top side should face the user as they hold the knife. 3. Slide the stud clip over the stud, glue in place without getting glue on the chassis. allow to dry. 4. Snip the stud at the marking spot, clean up as needed. 5. Glue the button to the top of the stud, again, the excess material should be on the user-side.