[Dominik]

Hi Craig!

I am engineer, but my first language is German. So my wording might not be the correct English. On a drawing you would actually get a 45 deg angle indicated for round material, resulting in 90 deg when you make it on a lathe (by turning it)

David posted a picture further up from his part. Have a look. I try to think of another example of a 90 deg tapered round material. A drill bit has 108 deg.

A pin-drive from a knock-off adapter, maybe ;-)

Or look at an ordinary wheel nut. They have an "angle" (taper, bevel) on the wheel side.

In our case, if the angle (or taper) from pin-drive and adapter are not the same, you create high forces on a small contact area. Worse, if that angle is not concentric, you create high forces on one side which will cause the pin to sit skew.

Then you can't get your wheel on. If you bend it straight, it will "relax" inside the wheel bend back and cause the wheel to stick.

Did that help?

Dom