they were, I am a cheap ass and don't want to spend 18 bucks a pop for the metal ones that rockler sells, found the plans on line to make them myself. used a old 2x4, jigsaw, and went to town. they work great!!!!!
Okay, I am calling B.S. on this "shop-made" hold down.
I am NOT impressed with this "cheap" hold down, because the photo shows commercially bought T-screw, knob, and T-track. The only part that is shop-made is the hold down bar itself. I am not sure that you save much with it. Besides, it doesn't have to be so fancy. A simple piece with a deep notch and rounded (sanded) edges would work fine and take a minute to make.
If you want a shop-made solution, I like what @allpurpose
did. It is truly shop-made.
You could also make the woodsmithtips' version with a T-track router bit, a hex bolt, a wing nut, and some scrap wood. True, the bolt and wing nut are "commercially bought", but they are cheap ordinary parts that you can find at the big box store, not specialty woodworking parts from the woodworking store.
(Confession: I have a box with a few of those commercially made "jig parts" in my shop, like those t-bolts and through-screw knobs. They are very handy. I also have ordinary hex bolts, nuts, and wing nuts, too.)