Step 21: T-Screw security system

[[br]]The T-screw has a T-shaped head, with flat sides. It can be turned using the special spanner. Quite often the application T-Screws are used for is blind fastening, where the head is inserted then crossed within a channel or slot and the fastened with a nut. In one common application T-Screws are the most secure way to hang a picture. Brackets are screwed onto the back of the picture frame and the screw is inserted into the wall, in accurately measured positions. The frame is then fitted over it, and the head turned to engage the channel of the frame using a security wrench key.[[br]]