Both razors use a wedge blade. I have 2 Henckle blades that came with the Rapide so I have a working blade for this. You can use a shimmed SE, it just doesn't feel the same. If you have a str8 with a chip on the edge you could cut it down to size and use that. That is after all, all these are. Str8 pieces set into a holder with a handle. I know that my Dovo would fit. The spines are the same width. So if ever I need a new blade I'll go shopping for a beat up straight and cut it down. Also to contrast the mechanical evolution of the two. The Rapide has to set screws that can be adjusted to reflect either different thickness blades or different exposures to the edge of the blade. The Comfort has a spring like mechanism that squeezes the blade then there is a lever in the back that keeps the blade engaged forward. It is interesting that this is the design that started safety razors. Now to find a "pig scraper".
