Originally I had a .STEP file that I converted into an assembly. All of the parts that I need to edit I have to use FeatureWorks on, or re-create, becasue sometimes I get a dialog box "Part contains overlaping features. FeatureWorks can not proceed any further". This particular part has "barrel bolts" or bolts with inner threads, see "Import 3" thru 6 in part file.  I am hoping to re-create this part so that I can edit it. Is there a way to imprt these bolts into the toolbox or create bolts like these?

Im still new at this so any expinations or points in the right direction would be most helpful. Thank you!

Note the attached file