I'm with Bill about getting educated on this, though, I had seen broaches before at tool auctions. Dredging up memories, the ones I saw back then were the pull type as used in a broaching machine. These have many incremental cutters that work as the tool is pulled through the piece. What was really interesting is what I learned at the Slater Tool site. That cutter you see in Rob's link looks simple but is only a small part of the operation. Slater's process involves a special tool holder that rotates due to the spinning of the work in a lathe and wobbles itself into the work, cutting tiny amounts with each wobble. I don't believe the Slater cutter can work without the Slater head.
Two other techniques I read about: use an index head in conjunction with a shaper (I actually got to use a shaper way-back-when in a community college machine shop class); heat the work piece red hot and drive the shaft through (no gaurantees from me).
Richard L.
