1. Part: Helical Sweep Create the solid model of a part by Helical sweep.
Click on Insert -> Click on helical Sweep -> Click on Protrusion (add material)/Cut (reduce material) -> select the options in Protrusion/Cut menu -> choose a sketch plane for sweep profile -> draw a sweep profile & a centerline -> give the pitch value -> sketch cross-section at sweep profile -> Done

2. Helical Sweep vs. Sweep
The sweep profile that gives the outer profile must be define
The cross-section must be defined at sweep profile
The centerline of sweep must be specified
The trajectory of the extrusion must be defined
The extruded cross section must be defined
The cross section stays normal to the path

3. Create a Constant Pitch Spring
Draw a constant pitch spring.
Modify the height of the spring.
Modify the pitch of the spring.
Modify the cross-section of the spring.
Modify the sweep profile.

4. Create a Variable Pitch Spring
Draw a Variable pitch spring.
How to change the pitch values at two ends.

5. Create a Screw Draw a screw. How to add chamfer at the end.
How to add relief-groove.

6. Screw #1

7. Screw #2