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
After watching this video, you can download the free PDF document and make it easily. There are many 90 degree corner clamp videos on youtube. But this is a little differ