Thanks for the reply. I can see now how the knob works.
I went to a couple of hardware stores today to see if I could find something to fix it but just decided to put a rod or bolt through the holes in the channel to keep it fixed in place (up) all the time. As it is, I hadn't taken down the ironing board in over two years so why do I need to have this one go up or down.
(My current ironing board is a cheapo from Craigslist that I bought when I - in a weirded-out moment - gave my some my old ironing board for his new apartment. What was I thinking?)
Now to make a long board to go on top...
Thanks,
Cathy