Revolve with variable section 1

[BiPolarMoment]

I have a part shaped roughly like a kidney bean (see attached) that I'm attempting to create thru holes that follow the profile of the front (cylindrical) AND top/bottom surfaces (curved w/ draft angle) .

The overall geometry was created via a loft where the cross-section drafts inward 3.5*/side (only the top and bottom surfaces). It is then extrude-cut into the kidney bean shape.

If you look at the file I've attached I've revolved a triangular profile (7* isosceles triangle) on an axis at the center point of the front cylindrical face creating a sort of drafted hole thru the part. In addition to this, I'd like it to taper off in like manner to the top/bottom surfaces to create a constant wall thickness i.e. when viewed from the front the top and bottom surfaces of the hole should appear concentric to the top and bottom surfaces, respectively, of the part.

What I've attempted to do and failed, was constrain the triangular cross-section to a curve projected onto the front face (offset from the top profile) with the intent that the cross-section would grow/shrink as it revolves. This either does not work or I've done it incorrectly--the result is illustrated in the picture attached.

Any tips for creating this feature? The other option I haven't explored yet is creating a 3D sketch on the front face with the desired hole size and extrude-cut it towards the centerpoint of the face with a 3.5* draft. I don't know if this would work or not.

 

[TheTick]

Create offset surfaces for where you want the hole surfaces to end up, the use Replace face to replace the nearly-matching surface with the one you want.

 

[BiPolarMoment]

Thanks, that does seem to work--I tend to forget about the surfaces tools. I usually assume that if I cant think of how to do it with a solid, then creating the surface won't be any easier that isn't the case this time.