I have built four of these frames. The first pictured I have been using for maybe a year or two and bought the clamps. The last three I have made I have built my own clamps with openbuild parts. I am still working on the design. At present I use wedges to apply pressure to the side of the wood and block. I am working on a cam system to apply pressure. I just bought 8mm screws with Knobs for quicker adjustment. I will update the build when I make these improvements.