OK Max,
Obviously I have never had a Victa like that. So the hole in the blade disc is round is it? Not diamond shape at all? Although I think the bolts I had here had one side ground flat. They were on a Victa I had here with diamond shaped holes and were very sloppy to say the least. I replaced them with ordinary diamnd shaped bolts. All good then.
I learn something almost every day from this forum.
Jeff