This quickie will show you How to Draw A Screw using Inkscape.
Start with a vertically long Rectangle.
Give it a Gray color.
Add Nodes to each side, about 17 total on each side (more if you want).
Select every other Node on the left side and drag it inwards.
Select every other Node on the right side and drag it inwards, but make sure the selected nodes are offset by 1 Node compared to the left side.
Smooth all the nodes you dragged inward.
With your Pen Tool draw a diamond shape going from one left edge to the right edge.
Smooth the center nodes, remove the Stroke, and give it a lighter color.
Duplicate this shape for each pair of edges.
Drag the bottom left Node slightly inwards.
Then drag the bottom right Node to the center.
Select the bottom edge's nodes and scale it down to make it smaller.
Create an Oval shape for the head of the screw.
Make a vertically long Rectangle with a dark shade of gray.
Duplicate it and move the duplicate aside.
Take the Difference of one of the rectangles.
Then drag the Duplicated rectangle to fill some of the spot.
Use the Pen Tool to create lighting and shading shapes.
Give them Lighter or Darker shades and slightly blur them.
Add more Shading to the bottom of the screw if you feel you need to, and you'll have yourself a Screw!