It's called the poor mans band saw, probably because it's cheaper and so much easier to build. For blades you can use a band saw blade of a size according to your needs, cut it up into 20" lengths and punch pin holes in the ends, you may have to heat the ends to avoid cracks in the punching process, inexpensive and easy.
It has been said that all the machines a wood turner (spindle or bowl) needs in addition to the lathe is a band saw and drill press. This walking-beam is a perfect and easier alternative to the band saw. It will rough out huge chunks of wood for the bowl turner and do the diagonal center cuts for centering spindle work.
It's not high on my list but I would love to build one of these for my ventilated shop space. It would handle rough construction type work, and do the work of a slew of saws like the band saw, table saw, miter saw, radial arm, and yes, even work that is to large for the regular scroll saw.
The build and plan are by Mark White, back in 1980 he was a teacher of house construction and boat-building at Alaska Community College. This article was published in Fine Woodworking # 24 - 1980.
Does the frame design look familiar to you? Yes, it does to me too. Back in 1943 Popular Mechanics published a plan for a foot powered scroll saw in their Shop Notes, that had a similar frame design. If you would like to check this out, here is the link to that post.