Old Secateurs

These old printers are very nice, feel good in the hand, the blade is sharp.
They don't cut well, and I think it's due to the gap between the blade and the hook.
Any ideas on how to fix this ?

can the nut or what have you in the middle be tightened?

Good idea, but I checked, it's as tight as it will go.
I think the end of the bolt was mushroomed out so it can't back out.