Ever look inside a cotter?

A cotter is a mechanism like the quill lock on a bridgeport. Guy
Lautard describes them and how they work in one of his "Machinist's
Bedside Reader" books and I borrow the term "cotter" from him.

I've made and used them in a number of metal projects but I'd never
taken a close look inside. Now that I'm learning to use 3D modelling
I did that --and found it interesting. Perhaps a few readers here
will also, No news to many readers but it was interesting to me.

I've posted screenshots in the dropbox as cotter*.jpg. I was
contemplating making a cotter clamp for the LED ringlight I'm
building for my microscope. The mount for the ringlight to the scope
is made using PVC plumbing parts from Home Depot as raw material
costing less than 2 bux.

In the model, the large part is a (nominal) 2" PVC collar, cotter
barrel is (nominal) 1/2" PVC pipe, the slugs in the cotter would be
turned from delryn to slide easily in a .625 hole reamed into the
small pipe, the pinch screw would be 1/4-20 brass. The cotter barrel
is 2" long. PVC is neat stuff because it's cheap and because glue
works well.

I think I'll try a simple setscrew first, but if that isn't
satisfactory I'll have this as a fallback. I do like making cotters!

The thing that struck me in looking at the model was the double
mechanical advantage at work to pinch tight: screw plus wedge. No
wonder these things work so well!