Amazing what you can find on eBay sometimes ;) :)
https://www.ebay.com.au/itm/204572694237?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3D107897cff9ef46cab316613920dc1197%26pid%3D100667%26rk%3D3%26rkt%3D8%26sd%3D325619052872%26itm%3D204572694237%26pmt%3D0%26noa%3D1%26pg%3D2351460&_trksid=p2351460.c100667.m2042 (https://www.ebay.com.au/itm/204572694237?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3D107897cff9ef46cab316613920dc1197%26pid%3D100667%26rk%3D3%26rkt%3D8%26sd%3D325619052872%26itm%3D204572694237%26pmt%3D0%26noa%3D1%26pg%3D2351460&_trksid=p2351460.c100667.m2042)
Heinisch_button hole cutter_1_cs.jpg
I have one too. :)
Like the depth gauge. Mine hasn't one so will have to "photo copy" and make one.
I think mines all there. I find it a bit awkward in reality, and it could be sharpened.
I acually prefer a nice sharp chisel.