FYI Eclipse used to make a "pad handle" to hold broken hacksaw blades. Holds blades in either direction. They look like a big Stanley utility knife handle, the old #99 model, and are cast metal - called a no.12 pad saw handle and there are several on eBay right now for under a tenner (no longer made AFAIK)
At a pinch, just wrapping several layers of tape around a blade works, but a blade holder wouldn't be that difficult to carve out from a bit of timber.

