I am building a custom hub and want to know what this is.

The hub will use an odd axle that is held on by removable (replaceable) studs.

The only cruiser front wheel I have is a Worksman with a front drum, and it uses an extra-thick axle compared to normal bruiser bikes, so I know it's not the same.

The Sheldon site says 9x1mm, but I'd rather use an English size because (me being in the USA) English sizes are common hardware-store fittings that are much more easily replaceable. Problem is,,, the Harris page says the equivalent English size is 3/8-26, which matches no tap or die I've ever seen. 3/8-24 is a National Fine Standard size. Is this an error on the Harris site, or are the old English axles really threaded 26 TPI?

edit-sheldon/harris page added-

http://www.sheldonbrown.com/harris/axles.html