https://somersetshop.co.uk/old-vintage-cast-iron-chaff-cutte...
I did find another, very different, device in this French news article which is a peat press in a Paris museum exhibit about Kerguelen, which was mistakenly called a "penguin press". It was actually used to make peat bricks, either as building material or as fuel.
So is there some myth that means that any press-like device on Kerguelen is assumed to have been used on penguins?
https://la1ere.francetvinfo.fr/2015/04/06/la-decouverte-des-...
It was "common knowledge" but I'm not that surprised either to hear that it's wrong.
If they have any oral history or anything of the sort...
Whether for using as fuel or for rendering their fat, they were not butchered to get only the useful parts and were processed whole instead (which is why the oil was often contaminated with feathers as the article says).
But I wasn't there then of course, and it's not described in "15,000 Miles in a Ketch", one of the best accounts of the era that I know of. Maybe it's better talked about in "Narrative of the Wreck of the Favorite on the Island of Desolation" because the author, John Nunn, was taking part in a more "industrial" seal harvesting operation but I haven't read it yet. In any case I recommend reading at least the first of these books, and the second book is likely interesting as well if one is curious about that era.
https://ssz.fr/brdl/presse-manchots.jpg
I took it on Kerguelen island, that's not a very good picture but you get the idea, a nice engineering detail is that the handle that turns the spiked rollers also has a blade and slices the pressed penguins into smaller slices.
Most of the time though (at least on Kerguelen) penguins were only used as fuel to render seal oil. The penguin oil itself was not used as much because it was less valuable.
Edit here's another picture of the same tool which better shows it maybe:
http://2.bp.blogspot.com/_etp6gd-6WC0/TOpnWK6ZBYI/AAAAAAAABR...