My old tube clamping blocks were made from a 2x4, a process that took me about 5 minutes with a circular saw and a set of spade bits. Yes, they sucked really bad. But they worked well enough, so I used them for 5 years and probably 300 frames.
But these are way nicer. Thanks to Erik (and his frakkin awesome woodshop at UofA) for making these for me. I'm psyched!
For those who are curious, I believe they are poplar.