I had the same issue (brass threads sheared off) with one of the '28 tripods that I received from OOW last year (Jan 07). This is when they had them. Afterwards, it took several emails and phone calls to keep reminding OOW to keep an eye out for one that they could swap out. I finally just mailed the part off with a letter and sat back. A month or so passed and eventually (I believe late March) they came thru with the entire T/E. Which was a bonus as I only really needed the brass knob itself. So it maybe a long shot now (1 year later) that they have any left, but do keep trying a couple of times before giving up on them.