DIY Rods, rod spacing question

[Tony B]

I'd like to make a set of DIY rods to put a DIY follow focus and mattebox on and wanted to know what the spacing is between the two. I know the rods are 15 mm but didn't know the spacing.

Does anyone know where I could find some plans for this?

Thanks

[thisiswells]

60mm

[Tony B]

Is that inside to inside,outside to outside, center to center?

[Erik Olson]

60mm on center.