Tutorial - Making a helical gear in AutoCAD?

Here is the tutorial
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Step 1:
Start AutoCAD.
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Step 2:
Make a circle of 35mm radius at center.
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Step 3:
Make another circle of 50mm concentric to previous one.
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Step 4:
Make two arcs like this one for cutting teeth.
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Step 5:
Trim down the circles. Now enter PEDIT command.
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Step 6:
Right click on the screen and select multiple.
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Step 7:
Select all arcs.
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Step 8:
Press enter and keep the input Y and press enter.
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Step 9:
Now click on the join.
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Step 10:
Press Enter.
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Step 11:
Now we can see that it has become a polyline.
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Step 12:
Enter helix command.
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Step 13:
Enter the radius value of (0,35). Any other value will distort the sweep. Keep the default value for the upper radius. Press Enter.
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Step 14:
Now select turns and enter a value of 0.15.
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Step 15:
Now enter a height of 50mm. We have helix path generated which will later be used for cutting the teeth.
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Step 16:
Create a circle of 50mm with origin as center.
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Step 17:
Extrude it by 25mm.
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Step 18:
Enter SWEEP command.
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Step 19:
Select the polyline to sweep and press enter.
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Step 20:
Right click and select alignment.
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Step 21:
Select No.
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Step 22:
Again right click and select twist.
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Step 23:
Keep the default values and press enter. Now select the helix as the sweep path.
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Step 24:
We have one cut body generated.
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Step 25:
Now enter array command.
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Step 26:
Select array type polar and enter origin as center for array. Click select object and select the sweep. Now enter the no. of items be 10. Click OK.
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Step 27:
Subtract the arrayed sweeps from the cylindrical body and we have the helical gear created.