For them there infernal threads, I just machine a groove around the bottom end of the hole that is to be internally threaded. When the tool cuts into the open space, you can hear it stop removing metal and so you jerk the half nut out of engagement. Of course you can't let your mind wander very far away from the job while employing this method!! Jesse in cooler W Tennessee MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.