How to create this drawing

i am stuck in this drawing(inside black circle part) please help me

Hi, it is a Mirror part of whole object so first of all you need to draw only one side of the whole object, and remaining matter is that how to draw one side part so i think to draw this shape you can use Tan Tan radius circle option to make this , first you can make circle of dia 66 mm as consider the center of this circle to center of part that is 65 mm from top circle part then you can make tan tan radius circle of R20 with make tan with R10 (lower side circle) & tan with circle of dia 66 mm so then trim unwanted part or portion which you don’t want. And other upper circle is also done by using same condition you can draw circle tan with R10 and tan with same center circle of dia 66 mm and trim unwanted portion so your half part is ready and then mirror it. Right so this is the Possible Method.

and the lower part under black circle (your Eqnuiry) is also done by Tan Tan Radius. OK try it if you face any problem then i am ready to solve it.