Ned: I could post further responses to what you've said, but apart from
a few minor points I agree with you. Were we face-to-face we could
discuss the merits of different models and likely reach an agreement on
a good one fairly quickly, but it's rather hard via Usenet. Usenet does
tend to be a little combative.

Bill: I am none the wiser. If you believe my FBD to be incorrect, please
explain clearly where you believe I should add or remove forces and why.
Better still, draw your own FBD and post it. Then I'll be glad to
discuss it with you.

Best wishes,

Chris