Today using Autocad I added an opening on the end of the previous spanner that I had cut for the Baruffaldi powered tooling to hold the flat on the 90 degree unit.
All looks exactly as I want in Autocad, as a .DWG. I then save it as a .DXF and within Autocad it still looks fine. If I then import the .DXF into SheetCAM in preparation for cutting on the plasma table, a mysterious circle appears between the jaws of the original spanner.
If I go back into Autocad there is no sign of this circle. Only one layer is in use, and if I do a 'LIST' selection of where the circle is, there is no circle listed

Now I'm sure that if I went back to the original drawing and started over, this strange artefact in all probability would not be there, as if I load the .DXF of the spanner that I originally cut, the circle isn't there. But that's not good enough - a chap needs to know WHY? and HOW? so come on chaps save my sanity, where is this circle in the .DXF that doesn't show in Autocad and yet does in Sheetcam.
NB the file "ER32-Spanner-Mk2-dxf-as-txt.txt" as it's name implies is ACTUALLY the DXF renamed so that it will upload to the forum.