I'm trying to mate the ID of a torsion spring to the OD of a pin. I can pick a point on the center of the spring and do a concentric or coincident constraint on the OD surface of the pin. Those are the only features that will work. The spring is then fixed in place and will not rotate on the...
The mid-priced modelers don't do well with complex surfaces and shapes. However, this may work for you. Using the Top and Front planes, draw the top and front views of your blade in 2d. Create an exact center line of each sketch and use them to extrude two surfaces that intersect each other...