I have a small vise, maybe two, made of steel that looks just like yours. It does appear the clamp has been modified, the name may have been cast into that. Since aluminum is much easier to cast and work than steel, and would be lighter for shipping, my guess is that its an early Japanese import. The wear of steel threads in an aluminum body would mean a shorter life. Possibly why we don't see more of them? Still an interesting shop tool. Just my guesses.