The safety meck-a-nysum has a square hole in it that fits over the safe-tee button thingy that hangs down inside the ree-see-vur. Sometimes the meck-a-nysum needs tweaking (bent up) to go over the safe-tee square button thingy hanging down inside the ree-see-vur.
All-sew, the meck-a-nysum thingy has an arm that goes from top to bot-tum about 2" long and 1/4" wide, at an angle. An arm, see it? Makes sure it's not bent out sideways a-rubbin on the inside of the wood thingy , a bindin up-like.
couldn't have said it better myself.
actually I tried and couldn't say it!