Holes in mesh

I have a tapered cylindrical mesh into which I have cut a hole using the “to sphere” command and extruded it into the cylinder to create the depth of the hole. Most of it is fine except it has left a mess at the mouth of the hole on the surface of the cylinder which has pushed the surface up a little. I am using this for a cnc routing project and the height around the hole perimeter will not be acceptable. Does anyone have a neater way of cutting the hole or perhaps a fix for the one I have? I have also used the “Surform” modifier. I have attached the mesh.

Thanks in advance for any help.

Attachments

ChanterD5.blend (696 KB)

Zoom right in to problem areas and you should see what may be causing the grief.


I’ve done that but there are so many vertices going so many different direction that must all stop at the surface it doesn’t seem practical to do it this way. Incidently there are 10 of these holes to be inserted. I was hoping that Blender could take care of this type of thing pretty much. You may have already gathered that I am an enthusiastic newbie.

I’d recommend dumping the current blend and start again. Make it simpler, the more high resolution the mesh the messier it’ll be and more difficult to clean up. If the holes are all the same, make one and then duplicate it for the others.
Look at the boolean modifier or other retopology tools to get a cleaner cut.
http://www.blendercookie.com/2011/01/28/tip_boolean_modifier/
http://www.blendercookie.com/2010/12/28/tip-hole-curved-surface-revisit/

I’m a Noob too eoinie and have ended up with similar. As Richard states above , bin it and start again, taking care with extruding/scaling

It’s just lack of practice/use of blender really.

Will do. Thanks for the help guys and for the links Richard