The first style can be dropped in anywhere but doesn't lock, while the second and third style can lock but must be slid in from one end. I think the...
How much do you need, and where are you located in the Philly area? I've got this piece leftover from when I used part of it to make my router table...
I do the same with mine, although I can't remember if I got the idea from the Extreme Woodworker or not (been a while since I watched that video and...