Choose Create, Line, Perpendicular.
Line perpendicular ribbon bar
|Use this ribbon bar to create a line perpendicular to existing entities. Create the line’s first endpoint by selecting an existing line, arc, or spline. Mastercam then displays a line that you can slide into the position you want. Choose the line’s second endpoint by clicking in the graphic’s window.By selecting the ribbon bar’s Tangent button (), you can create a line that is both perpendicular to a line and tangent to an arc. First, select a line or arc. Then select a second line or arc. (Select an arc if the first entity you chose was a line, and a line if the first entity you chose was an arc.) When you choose the second entity, Mastercam creates multiple line possibilities and prompts you to select one to keep.
To set the length of the perpendicular line, enter a value in the Length field, press [Enter], and then select the two existing entities. As long as the perpendicular line remains live, you can also use the Length field to change its length.
1 – Edit endpoint 1 (edits endpoint)
F – Flip
L – Length (defines line length)
T – Tangent (creates lines tangent to an arc)
P – Apply
O – OK (fixes live entity and exits function)