Wadkin Jointer knife bolt size

[BobL]

A friend of mine is in town from the country.
He has a 12" Wadkin Jointer and has damaged a bolt that holds the knives in place and would like to get a replacement.
Does anyone know the size for this bolt so he can buy one while he is in town?

Here's a picture of said item.
TimCJBolt.jpg

Thanks

[wallace1973]

5/8ths seems to ring a bell but not 100% sure, I had to have a new stud made for my MJ and the nut I got stood too proud so I had to grind some off. You have to balance the nut as well. Ideally you want the proper domed nuts