The hard part is finding a off the shelf shoulder bolt that is long enough, imperial ones dont seem to be long enough and 6mm metric are easy to get but are .25mm too small dia so will no doubt still cause issues.

The lathe is currently being fitted with a new backplate so cannot make a custom bolt to fit at the moment and I am not willing to pay the silly amount for a merc bolt and I have a merc and x2 supersports to do.

From what I can tell all you have to do is drill out the old pin hole slightly to fit the shoulder bolt and nut and then stick it through and tighten.