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AutoCAD Tutorial

Creating a 3D Screw

By Robert Southworth

In this AutoCAD tutorial, we will create a 60-degree V slotted screw. It is a 20mm x 8mm screw with a pitch of 1. You may alter it to your own size later on, but follow this tutorial first till you are comfortable with the process.

Draw a rectangle 20mm x 8mm offset the right hand line a mm (Half Pitch) and then offset this line1mm (full Pitch)

Draw a line from the bottom of the .5-offset line to the top of the 1mm offset line. Copy this across to the bottom of the 1mm Offset line (See Below)

Draw 60 degree Vs from these 2 new lines and trim back as shown below.

Fillet the opposite angled lines with a Radius of 0 to create the triangles shown below.

Draw a long straight line to the right of the drawing and copy this to the left as shown below. Make sure the line is very long, as we need to extend lines to them.

Extend the lines indicated in red to the long lines as shown below and trim back.

Now draw a straight line from the Apex of the left triangle to the left long line and trim and erase away the bottom of the triangle. As shown below.

Now draw a line from the Apex of the right triangle to the right long line of the triangle and trim and erase the top away. The drawing should look like below.

Pedit the 2 triangles and revolve them about themselves. Create a 20mm x 8mm Cylinder at the midpoint of the Left line of the rectangle and rotate it 90 degrees using the bottom and top of the left-hand line on the rectangle as the Axis. (You could set your UCS to do this) but I just rotate it. The drawing should look like below. (South West View)

Next Subtract the 2 Cones from the Cylinder. Set the UCS using the Object option and one of the red lines shown below
Slice the object using the ZX option along the left hand line only marked in Red as shown below.

Delete the part to the left (Major part of cylinder).

Set the UCS back to World. Use the southwest view and slice the part in half. Using the 2 points on the right hand side of the rectangle and the bottom left corner. Delete the top part. You should be left with below.

Copy the part and rotate it 180 degrees as shown below.

Align the 2 parts as shown below.

Your part should look like below. (It may start to make a bit of sense now)

Union the 2 parts and array it with 1 row 20 columns and a distance of -1 (Pitch).
Union the arrayed parts.
Draw a 30mm x 8mm Cylinder similar to before and rotate it 90 degrees.
Subtract the arrayed parts from the cylinder. Slice off the end as it has overlapped. Add a bolt head or Screw Head. And the drawing  - once rendered - should look as below.

About the Author

Robert Southworth is a lecturer in computer aided design, with an emphasis on MCAD, in the United Kingdom.

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