I make long C clamps using some hard plywood. You can do a lot of compression with these extra powerful clamps. It is very useful thanks to its long arms. It is also strong enough to break the board. After downloading the dimensions PDF and watching this video, you can easily make Extra Strong Long C clamps. Adjustable distance very useful.
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PDF Download : Extra Strong Long Reach C-Clamps
Did you see this ? GreenSaw G Clamps
I make a small hand planer in this video. I use a 41mm width blade I bought and some hard wood. I made a great hand planer.