Allen screws made from weak metals strip quickly, and using the wrong size Allen wrenches/hex ... of drops to the stripped screw head. Then push your hex key into the screw and turn ...

In fact, both are hexagonal, and if you find the right size bolt, it will fit snugly into a hex screw. If you place a bolt upside-down (head first not threads) into the Allen screw, you now have a ...