Fast collisions

Hi maybe someone can help me, with a sword collision problem that ive been battling with for weeks!! Tried every forum but with out success . So the probem is at speed the colliders are able to pass through each other . I've tried every type of collider and combination of multiple staged collider to rigid body collision type to time step, scaling up and add force script but that only works in one direction so it has to be a physics answer to work in all directions. ANY IDEAS on what i may be able to do to solve this conundrum with such small thin colliders ? I enclose a link to show you what im up to . https://youtu.be/3GFkGV9UZ6s Any faster than this and blades pass through each other !!