I just bought a Bosch PFZ 500 E reciprocating saw for cutting small
blocks of wood to go in my woodburner. It's ok, not as fast as a
circular saw but rather less noisy which is good as I will be using it
often and it will annoy the neighbours less.

The manual suggests only using replacement blades with an 'M' shank.
Are these 'M SHanks blades' some kind of generic fit for other
electric saws. I hope so because the replacement Bosch parts are much
more expensive than jig-saw blades; I thought they would be similarly
priced.

Also, for interest, is there some kind of quiet cutting tool that
could slice its way through a floor joist sized piece of wood? I am
thinking perhaps of a slow turning saw but with high torque, or maybe
rugged highly leveraged guillotine?