Further daft questions about my fence build

[xillent]

I did promise a series of possibly daft questions regarding my fence build.

-I have Flat holed Bar with 12mm round holes. Should I buy 12mm round or 10mm round to fit through it? I'm concerned that 12 mm round is too much of an interference fit and I'll have trouble getting it through or that 10mm will lead to issue welding. I hope I've explained what I mean correctly.

-Also, I was going to use 50mm x 50mm box for the posts with a 3mm thickness. Is 3mm sufficient to be reasonable robust? It's just a fence in garden, not for stopping a car or anything.

Thanks, as ever, in advance

 

[xillent]

I think the 10mm round with 12mm hole in punch bar looks like the right way to go

 

[Domdom]

I made a small garden gate with those pre-drilled bits etc. I matched the sizes, all 10mm from memory. But on the punched bar I countersunk the back side of the holes for a weld pool. Then ground them flat.

 

[xillent]

I see Tunley rod sell them with a 2mm oversize hole