I'm able to create realistically looked image, but I need to draw a series of gears, which will be used in animation and my approach has several drawbacks, which will heavily complicate my quest.
The gears are always meant to be combined with other gears, right? And classical circular gears, if combined, has to have the same shape of involute to work together. So if I want to draw a inner gear with counterpart outer gear, I have to use the same shape of involute for both gears, but on inner gear, the involutes will be flipped towards center of a circle.
- We can use Inkscape Extension → Render → Gear to create a perfect classical outer gear easily.
- Duplicate that gear and on the duplicate remove all nodes except one involute.
- Flip the involute around, create a circle, slightly bigger than original outer gear, and place the involute to inner part of the new circle.
- Mark center of the circle, and to this center move the point of rotating of the involute.
- Duplicate the involute and while pressing Ctrl rotate duplicate by one step. Because we have the point of rotating in center of circle, the duplicates will move regularly on the circle.
- If you are lucky, after few finishing touches, you will end up with inner gear, which could be combined with original outer gear.

But this approach has one big issue. You cannot easily adjust the diameter of gears, because by stretching the gear, you are also changing its involutes.
Is there a way, how to use some oject as a stroke for another object?
Imagine I will have one involute used as a stroke of two circles. I can then change the diameter of the circles without changing its involutes or change the involutes of both circles by simply modifying one underlying involute object.