Hello Lorenz

It is highly unlikely the blade holder is original.
I have not found an 'original' machine that did not have rigid 'sickle' blades.
The early set-up was bar holder with rigid triangular blades.

There was no need for swing-back blades, given shock protection was afforded
via the belt drive.

As in ...

[Linked Image]

But nothing is certain here - we don't know how the Whirlwind slasher
developed over its production life. You are helping us out.

Please keep us informed of progress.

Cheers
-------------------
Jack

p.s. That's an interesting last image - with the Stilson 'fish'
exploring the workshop ocean floor.