binding barrel bolt meets a carriage bolt

good day -

first off! i am not a machinist - so you will have to be a bt forgiving.

i have a dilemma - i am working on this design - and the intent is that the (green) cylinder is to freely roll when applied to a surface (like a pizza cutter.)

however - the binding barrel (blue) i sourced out at mcmaster-carr - i do not want to rotate. and i certainly don’t want to too tight as it will start to bend the channel.

it’s also critical that the ends have no drive - but a nice polished-finished look.

maybe an adhesive?

i came across google images - where i can see a binding barrel with a hex at the base (like a carriage bolt) i think this would work - right?

but i imagine it’s easy to drill the hole in the channel - but the hex shape not so?

so i am at a loss.

if you look at the reference in the yellow circle - the bolt is normally welded and then sanded off. i don´t like this look. (unless there’s a machine shop that could perform this with a better finish?)

what are my options in achieving this function?

best regards -

jón