How to complete this PIECE by using tangency ?

Hi ,

I'm trying to draw this PIECE on AutoCAD but I get stuck on these highlighted Lines !

And this is the final result

Our teacher told us that we have to draw them by using "tangency". For example , draw 2 circles then draw the third one centered on the intercept between them .

But i couldn't figure out the connections between these circles and how to come up with intercepts !

Please excuse my poor English

For top, you may use Draw -> Circle -> Tan, Tan, Radius and trim out the outside part of the circle. The bottom edges use LINE command with the Tangent OSNAP mode activated. It will be easier for you to draw the R12 arcs as circles and remove later the un-wanted parts by TRIM.

Regards,

Mircea

Thank you Mircea ,

And I will try to apply it.

but before that ,

I think I couldn't explain the idea of intercept well !

and this picture may clarify it more

Try to imagine the full circle of each curve ( except the middle line )

Your teacher is trying to use drafting board techniques to find intercepts.

While that is sometimes appropriate - in this case it is not needed as you can use Tangent osnaps.

As you learn Parametric Geometry Constraints there is even fewer instances of the need to know these old geometry tricks in this century.

Thank you very much Sir,

I have applied all your valuable advices ( you and Mircea )

and this is the final result ( After 3 hours ) ..

I draw the right and the left sides by drawing line starting from the bottom outer circle then right click > snap overrides > Tangent.

the top curve ( R 76 ) :

I draw 2 circles centered in the left small circle and the right one and have 82.5 Radius. Then, from their intercept I draw third circle of radius 76 but this one has a concave up curve !

from its intercepts i used this command ( Draw -> Circle -> Tan, Tan, Radius ) to draw concave down curve.

Thank you so much all of you , I really appreciate your help

That's good. Now do it again. And when you're done do it again. Keep practicing.

Each time you do it you should get faster to the point where you should be able to knock it out in less than 3 minutes.

Attach the file here for checking.

Each time you do it you should get faster to the point where you should be able to knock it out in less than 3 minutes.

1 1/2 flat, but admittedly, I didn't do the centerlines or dimension the holes, which I assume are supposed to be 12D?

Moved to the Student Project Questions forum.