43249
Sadly the second to last is the most fragile knife I ever purchased. Didn't last more than 3 weeks.

There are other ways of course, anyone can build one. You need a piece of metal, drill a hole in the bottom of it, put in a pilot rivet with a hammer. Sand down the ends of it short, drill two more holes, use a hand tap and put in some threads. Get some torx screws and now the hardest part is finished.
Grab two equally sized pieces of metal, wood, or plastic. Cut a slot on both pieces (drill press with a cutting mill), enough for the piece of metal to fit into then line up each piece with the two holes drilled from eariler and drill the same hole/tap it again in the material you have chosen. Voila, you made one!