Extruding not Substracting as it Always did

I am trying to create a recess in a threaded tube (internal thread).
I draw a circle the size of the recess I need in different ways, but none are working as expected.

  1. on the objects face
  2. on a plane flush with the face I need to recess
  3. on a plane distant from the face I need to recess

Instead of recessing (substracting body), a new body is created.

When I reach a certain distance (larger than the recess I need, it starts working as it should. Why not right from the surface of the body?

Help please! :slight_smile:

https://support.shapr3d.com/hc/en-us/requests/new

There’s a tiny menu icon that pops up when you start the extrude. Click on it and select Subtract.

When you are attempting to create the “Recess”, will the recessed bit also have internal threads, or will those threads be removed with the recess leaving smooth internal walls?

Thank you very much, there was a little irregularity in the drawing that was not allowing extrusion…