Mark off two four-inch long lines parallel and on each side of the 270°- 90° axis on your converter disc so that their mid points lie on the 0 -180° axis and, of course, at right angles to this 0 -180 degree axis.
Maka ngokususa ii-intshi ezimbini kwimigca emibini emeleneyo kwicala ngalinye lika 270°-90° kwisitshintshi sakho secwecwe ukwenzela ukuba amanqaku aphakathi ahlale ku 0°-180° kwaye, ewe kwimbombo ezilungileyo ezingu 0°-180° wamanqanam