Modeling a gear in Shade

The goal in this tutorial is to model a reasonably elaborate gear. It is assumed that the person using the tutorial is familiar with the tools and interface of Shade. This is done in Shade 14E, but uses nothing that is not in previous versions. This is a good shape to learn many of the techniques of modeling with curved surfaces.
We begin by modeling the hub. A closed line is used.
Create this shape just above the centre line, and select these two points.
Right click to bring up a context menu, and select Iron.

In order to spin the profile into the hub, select Solid->Revolve.

Draw a line to give the profile an axis about which to revolve.
The hub in wireframe
The hub in perspective.
We will be a little more fancy with the outer ring. Draw this figure with Closed Line, and select these points.
Once you apply Iron again, this will be the result.
Using the same position as the axis of the hub, apply the revolve function and the outer ring is in place.
We will begin to make the spokes by drawing a disk that just fits the outer ring on the X axis.
Convert the disk to a line object. We will soon combine three lines using the Connection command, and line objects are required.
From the top view, choose Move->scale to make it fit on the Z axis.
It is now of a size that is completely hidden within the outer ring.
Make two duplicates, one in the hub and one between. Spacing is not critical.
Resize both ovals on the Z axis, so the bottom one fits in the hub out of sight. They don't have to be the same size.
With all three ovals selected, go to the Modify panel and select Connection. Now we have a spoke.
Choose Copy->Numeric. Click in the centre of the gear and set the rotate angle to 60°.
With all six spokes in place.
Now it gets a bit complicated and I will include more detail. We will begin modeling the teeth by creating a rectangle across the top of the outer ring. Be sure it is right on the centre line when viewed from the front. This will be the low part of the tooth.
We will end up by connecting four lines spaced 5° apart. To begin, Move-> Numeric by 7.5° on the Z axis.
Now create a rectangle that will be part of the high part of the tooth. Again make sure it is on the centre line.
To place it 5° from the previous line, Move->Rotate it 2.5°.
Switch to Copy->Numeric and copy it at -5°.
Select the first rectangle created and use Copy->Numeric to make a copy at the other end of the group, 15° away.
This step is critical. When you duplicate Closed Line 1, it will move to its proper position on the outer ring, but it will show up next to itself in the browser. You must drag it into its position as above. All four lines must be in the order in the browser that they are in 3D space.
With all four rectangles selected, once again use Modify->Connection to create the tooth.
Select these lines and click on Modify.
Grab the control points and bring the lines to about horizontal. It may take a bit of editing, to get the gears correct. Give it a try and refine if needed.
Since we were careful to make the tooth exactly 15° wide, we can use Copy->Numeric to replicate it around the outer rim.
View the gear, delete all but one tooth if necessary, and edit it. Repeat until it looks right. Surface it and render it as below.
©2013 Larry N.Bolch