Was going through things that popped up on my screen, while chasing another rabbit down a hole. This came up. It's a dowel jig using two saber saw blades.
Many ways to make dowels. What ever gets you what you need. I have a dowel plate that I just smash the wood through. The harder woods can come out a little rough with the plate
Yeah, the bash through a single hole does leave things rough. Great for joinery where the rough surface makes for a great glue bond, but not for something that needs to be functional like a hinge pin.