In this tutorial i will make a torsion spring the same as you can see in my models. I hope it will be halpefull for you.
Part. Choose top plane and start. Draw a circule D:3,60 mm and go under Features and choose (under Curves) Helix Spiral. Pitch is 2 mm and we will have 13 Revolutions. OK
Then choose Front plane to sketch and draw a centerline from the center up. Then draw a line and and choose 3 Point Arc and draw 2 half circules. Then draw a centerline like in the photo. Angle: 45 deg.
Smart Dimensions and close the sketch.
Open 3D sketch. Select Spline and draw a line like in the photo.
Then select the Spline and Line (hold Ctrl) and select Tangent. See the photo.
close the sketch. Choose the front plain and make the same on the other side.
Close the sketch and open 3D sketch Select Spline and draw a line. See STEP 4 and 5.
Now exit 3D sketch and go to Features and select (under Curves) Composite Curve and select all and OK
Now choose a plane (Reference Geo.) and select the Edge and Point like u see in the photo. and Sketch on that plain.
Draw a circule D: 0,8mm and close the sketch.
Features and select Swept Boss and select the circule u draw in the step 10 and the curve.
Now you are done.