Try drawing the latch shown.
1. Start AutoCAD, open a new file, and name it Latch .
2. When you get to the drawing editor, use the Line command to draw the straight portions of the latch. Start a line as indicated in the figure; then enter relative coordinates from the keyboard. For example, for the first line segment, enter @4<180-l to draw a line segment 4 units long from right to left. ,
3. Draw an arc for the curved part. To do this, click the Arc tool from the Draw toolbar.
4. Use the End point Osnap to pick the endpoint indicated in the figure to start your arc.
5. Type E-l to issue the End option of the Arc command.
6. Using the End point Osnap again, click the endpoint above where you started your line. A rubber-banding line and a .temporary arc. appear.
7. Type D-l to issue the Direction option for the Arc command.
8. Position your cursor so the ghosted arc looks like the one in the figure, and then press the mouse/pick button to draw in the arc.