If you work much with MDF, you know that the edges don’t have a great deal of holding power for screws, and it often splits. When I need to make a sturdier screw joint, I drill a slightly oversized pilot hole for my screw and fill it with epoxy. Before the epoxy sets, I warm it with a heat gun so it soaks into the MDF, then I drive the screw into place. The glue seems to reduce the tendency of MDF to split while creating much stronger “threads” for the fastener. Try it!