Infinitely small extrusion when extruding from curved surface

[wfp21]

I added a colinear constraint to a projected edge. The sketch is fully constrained, however after changing the dimensions of what I am extrude cutting onto, the following occurs:

An unwanted ifinitely thin line appears.

Perhaps an emboss cut is more suited as it is not a flat face, however I cannot seem to emboss at all.

Here is a link to the file if you'd like to play around: https://a360.co/3oyfkG8

Thanks in advance for any advice,

Will

[aliobidi]

Hi ,
you can just select the  thin line and delete it 
or you can project the outline of this thin line like in pic then cut it 

[laughingcreek]

the bit's that's left over isn't infinitely thin, it has some thickness to it.  it's happeing because the tangent plane isn't perpendicular to the face at the end, so your cutting through it at an angle.

this can also be solved using the approach I attached in your other post.  did you look at that model?

[laughingcreek]

not sure exactly what your after, but maybe the attached will give you an idea.