Modifying a hole on a part from a vendor's step file

[alphatozeta]

I download a sept file for a gear that has multiple holes on its face. They are plane holes and I want to modify a few to be countersunk holes. Is there a way to modify the part to change the holes to countersunk? Fusion360 doesn't seem to fully recognize them as holes to change them to countersunk holes and/or I don't know how to do it.

Thanks...

ref:

part#  615226

http://www.servocity.com/

[jeff_strater]

I would use the Chamfer feature to add the countersunk geometry to the hole.

Alternately, you can create a sketch on the face, and add a new hole with the same diameter (using Measure), then make that hole a Countersunk hole.

Here is a video showing how to do both of these methods:

Hope this helps,

Jeff